Audacity 2.4.2 + Win10: FFmpeg library not found

Hi, when I started Audacity, I received a message something like “FFmpeg library used to be installed but is missing, please try to locate it again.” I have tried to manually locate it, and Audacity defaults to the proper directory, but does not recognize the FFmpeg library. I have been successfully using Audacity 2.4.2 with FFmpeg for Audacity 2.2.2 under Windows 10 64-bit for quite some time.

I have tried uninstalling and reinstalling Audacity and FFmpeg for Audacity multiple times, with and without using the reset preferences option. I have tried reverting to older versions of Audacity (as far back as 2.2.2) with the same results. I have manually deleted the Audacity folders under \Users<username>\AppData\Roaming\audacity. I have tried using the zip version of FFmpeg for Audacity. Audacity simply has stopped automatically locating FFmpeg and refuses to recognize it when I manually locate it. Audacity continues to say: “FFmpeg Library Version: FFmpeg library not found” and does not report the expected version numbers. The “Program Files (x86)\FFmpeg for Audacity” folder exists and contains the required files. My system is updated. I have checked Windows for corrupt system files.

Any suggestions about what else to try? Is anyone aware of recent Windows updates that break FFmpeg?

References:
https://manual.audacityteam.org/man/installing_ffmpeg_for_windows.html
https://manual.audacityteam.org/man/installing_and_updating_audacity_on_windows.html

Here is the log file.

10:36:06: Audacity 2.4.2
10:36:06: Trying to load FFmpeg libraries...
10:36:06: mLibAVFormatPath ('C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll') is not empty. Loading from it.
10:36:06: Looking up PATH environment variable...
10:36:06: PATH = 'C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps;'
10:36:06: Checking that 'C:\Program Files (x86)\FFmpeg for Audacity' is in PATH...
10:36:06: Warning: FFmpeg directory 'C:\Program Files (x86)\FFmpeg for Audacity' is not in PATH.
10:36:06: Temporarily prepending ';C:\Program Files (x86)\FFmpeg for Audacity' to PATH...
10:36:06: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
10:36:06: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
10:36:06: Loading avutil from ''.
10:36:06: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
10:36:06: Loading avcodec from ''.
10:36:06: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
10:36:06: Loading avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
10:36:06: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
10:36:06: Returning PATH to previous setting...
10:36:06: Error: Failed to load FFmpeg libraries.
10:36:06: Trying to load FFmpeg libraries from default path, 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
10:36:06: Looking up PATH environment variable...
10:36:06: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
10:36:06: Checking that 'C:\Program Files (x86)\FFmpeg for Audacity' is in PATH...
10:36:06: FFmpeg directory is in PATH.
10:36:06: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
10:36:06: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
10:36:06: Loading avutil from ''.
10:36:06: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
10:36:06: Loading avcodec from ''.
10:36:06: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
10:36:06: Loading avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
10:36:06: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
10:36:06: Error: Failed to load FFmpeg libraries.
10:36:06: Trying to load FFmpeg libraries from system paths. File name is 'avformat-55.dll'.
10:36:06: Looking up PATH environment variable...
10:36:06: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
10:36:06: Checking that '' is in PATH...
10:36:06: FFmpeg directory is in PATH.
10:36:06: Checking for monolithic avformat from 'avformat-55.dll'.
10:36:06: Error: Failed to load shared library 'avformat-55.dll' (error 127: The specified procedure could not be found.)
10:36:06: Loading avutil from ''.
10:36:06: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
10:36:06: Loading avcodec from ''.
10:36:06: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
10:36:06: Loading avformat from 'avformat-55.dll'.
10:36:06: Error: Failed to load shared library 'avformat-55.dll' (error 127: The specified procedure could not be found.)
10:36:06: Error: Failed to load FFmpeg libraries.
10:36:06: Error: Failed to find compatible FFmpeg libraries.

I’d suggest that you completely uninstall FFmpeg, then look in "C:\Program Files (x86)" and delete the “FFmpeg for Audacity” folder (if present).
If you see any other folder called “FFmpeg for Audacity”, delete that too.

Then download a fresh copy of “ffmpeg-win-2.2.2.exe” from here: https://lame.buanzo.org/#lamewindl

Before installing it, reboot your computer.
Then double click on the downloaded “ffmpeg-win-2.2.2.exe” file to run the installer.

Then go to the hidden folder:

Users\<username>\AppData\Roaming\audacity\

(where is your user name)
and delete the file “audacity.cfg”.

Then launch Audacity 2.4.2.
Check near the bottom of the Audacity log and hopefully it will say that FFmpeg has been successfully loaded.

I followed all instructions, but, unfortunately, that did not repair it. Anything else to try, short of re-imaging my system? :slight_smile:

14:13:50: Audacity 2.4.2
14:13:50: Trying to load FFmpeg libraries...
14:13:50: Trying to load FFmpeg libraries from default path, 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:13:50: Looking up PATH environment variable...
14:13:50: PATH = 'C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps;'
14:13:50: Checking that 'C:\Program Files (x86)\FFmpeg for Audacity' is in PATH...
14:13:50: Warning: FFmpeg directory 'C:\Program Files (x86)\FFmpeg for Audacity' is not in PATH.
14:13:50: Temporarily prepending ';C:\Program Files (x86)\FFmpeg for Audacity' to PATH...
14:13:50: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:13:51: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:13:51: Loading avutil from ''.
14:13:51: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:13:51: Loading avcodec from ''.
14:13:51: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:13:51: Loading avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:13:51: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:13:51: Returning PATH to previous setting...
14:13:51: Error: Failed to load FFmpeg libraries.
14:13:51: Trying to load FFmpeg libraries from system paths. File name is 'avformat-55.dll'.
14:13:51: Looking up PATH environment variable...
14:13:51: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
14:13:51: Checking that '' is in PATH...
14:13:51: FFmpeg directory is in PATH.
14:13:51: Checking for monolithic avformat from 'avformat-55.dll'.
14:13:51: Error: Failed to load shared library 'avformat-55.dll' (error 127: The specified procedure could not be found.)
14:13:51: Loading avutil from ''.
14:13:51: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:13:51: Loading avcodec from ''.
14:13:51: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:13:51: Loading avformat from 'avformat-55.dll'.
14:13:51: Error: Failed to load shared library 'avformat-55.dll' (error 127: The specified procedure could not be found.)
14:13:51: Error: Failed to load FFmpeg libraries.
14:13:51: Error: Failed to find compatible FFmpeg libraries.
14:13:57: Using internal LAME
14:14:04: Trying to load FFmpeg libraries...
14:14:04: Trying to load FFmpeg libraries from default path, 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:04: Looking up PATH environment variable...
14:14:04: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
14:14:04: Checking that 'C:\Program Files (x86)\FFmpeg for Audacity' is in PATH...
14:14:04: FFmpeg directory is in PATH.
14:14:04: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:04: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:04: Loading avutil from ''.
14:14:04: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:04: Loading avcodec from ''.
14:14:04: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:04: Loading avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:04: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:04: Error: Failed to load FFmpeg libraries.
14:14:04: Trying to load FFmpeg libraries from system paths. File name is 'avformat-55.dll'.
14:14:04: Looking up PATH environment variable...
14:14:04: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
14:14:04: Checking that '' is in PATH...
14:14:04: FFmpeg directory is in PATH.
14:14:04: Checking for monolithic avformat from 'avformat-55.dll'.
14:14:04: Error: Failed to load shared library 'avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:04: Loading avutil from ''.
14:14:04: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:04: Loading avcodec from ''.
14:14:04: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:04: Loading avformat from 'avformat-55.dll'.
14:14:04: Error: Failed to load shared library 'avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:04: Error: Failed to load FFmpeg libraries.
14:14:04: Error: Failed to find compatible FFmpeg libraries.
14:14:04: Looking for FFmpeg libraries...
14:14:04: mLibAVFormatPath is empty, starting with path 'C:\Program Files (x86)\FFmpeg for Audacity', name 'avformat-55.dll'.
14:14:05: User-specified path = 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'
14:14:05: User-specified FFmpeg file exists. Success.
14:14:05: Trying to load FFmpeg libraries...
14:14:05: mLibAVFormatPath ('C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll') is not empty. Loading from it.
14:14:05: Looking up PATH environment variable...
14:14:05: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
14:14:05: Checking that 'C:\Program Files (x86)\FFmpeg for Audacity' is in PATH...
14:14:05: FFmpeg directory is in PATH.
14:14:05: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:05: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:05: Loading avutil from ''.
14:14:05: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:05: Loading avcodec from ''.
14:14:05: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:05: Loading avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:05: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:05: Error: Failed to load FFmpeg libraries.
14:14:05: Trying to load FFmpeg libraries from default path, 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:05: Looking up PATH environment variable...
14:14:05: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
14:14:05: Checking that 'C:\Program Files (x86)\FFmpeg for Audacity' is in PATH...
14:14:05: FFmpeg directory is in PATH.
14:14:05: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:05: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:05: Loading avutil from ''.
14:14:05: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:05: Loading avcodec from ''.
14:14:05: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:05: Loading avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:05: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:05: Error: Failed to load FFmpeg libraries.
14:14:05: Trying to load FFmpeg libraries from system paths. File name is 'avformat-55.dll'.
14:14:05: Looking up PATH environment variable...
14:14:05: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
14:14:05: Checking that '' is in PATH...
14:14:05: FFmpeg directory is in PATH.
14:14:05: Checking for monolithic avformat from 'avformat-55.dll'.
14:14:05: Error: Failed to load shared library 'avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:05: Loading avutil from ''.
14:14:05: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:05: Loading avcodec from ''.
14:14:05: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:05: Loading avformat from 'avformat-55.dll'.
14:14:05: Error: Failed to load shared library 'avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:05: Error: Failed to load FFmpeg libraries.
14:14:05: Error: Failed to find compatible FFmpeg libraries.
14:14:07: Trying to load FFmpeg libraries...
14:14:07: mLibAVFormatPath ('C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll') is not empty. Loading from it.
14:14:07: Looking up PATH environment variable...
14:14:07: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
14:14:07: Checking that 'C:\Program Files (x86)\FFmpeg for Audacity' is in PATH...
14:14:07: FFmpeg directory is in PATH.
14:14:07: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:07: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:07: Loading avutil from ''.
14:14:07: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:07: Loading avcodec from ''.
14:14:07: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:07: Loading avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:07: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:07: Error: Failed to load FFmpeg libraries.
14:14:07: Trying to load FFmpeg libraries from default path, 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:07: Looking up PATH environment variable...
14:14:07: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
14:14:07: Checking that 'C:\Program Files (x86)\FFmpeg for Audacity' is in PATH...
14:14:07: FFmpeg directory is in PATH.
14:14:07: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:07: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:07: Loading avutil from ''.
14:14:07: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:07: Loading avcodec from ''.
14:14:07: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:07: Loading avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:07: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:07: Error: Failed to load FFmpeg libraries.
14:14:07: Trying to load FFmpeg libraries from system paths. File name is 'avformat-55.dll'.
14:14:07: Looking up PATH environment variable...
14:14:07: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
14:14:07: Checking that '' is in PATH...
14:14:07: FFmpeg directory is in PATH.
14:14:07: Checking for monolithic avformat from 'avformat-55.dll'.
14:14:07: Error: Failed to load shared library 'avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:07: Loading avutil from ''.
14:14:07: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:07: Loading avcodec from ''.
14:14:07: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:07: Loading avformat from 'avformat-55.dll'.
14:14:07: Error: Failed to load shared library 'avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:07: Error: Failed to load FFmpeg libraries.
14:14:07: Error: Failed to find compatible FFmpeg libraries.
14:14:07: Looking for FFmpeg libraries...
14:14:07: mLibAVFormatPath ('C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll') is not empty.
14:14:09: User-specified path = 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'
14:14:09: User-specified FFmpeg file exists. Success.
14:14:09: Trying to load FFmpeg libraries...
14:14:09: mLibAVFormatPath ('C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll') is not empty. Loading from it.
14:14:09: Looking up PATH environment variable...
14:14:09: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
14:14:09: Checking that 'C:\Program Files (x86)\FFmpeg for Audacity' is in PATH...
14:14:09: FFmpeg directory is in PATH.
14:14:09: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:09: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:09: Loading avutil from ''.
14:14:09: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:09: Loading avcodec from ''.
14:14:09: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:09: Loading avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:09: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:09: Error: Failed to load FFmpeg libraries.
14:14:09: Trying to load FFmpeg libraries from default path, 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:09: Looking up PATH environment variable...
14:14:09: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
14:14:09: Checking that 'C:\Program Files (x86)\FFmpeg for Audacity' is in PATH...
14:14:09: FFmpeg directory is in PATH.
14:14:09: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:09: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:09: Loading avutil from ''.
14:14:09: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:09: Loading avcodec from ''.
14:14:09: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:09: Loading avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:14:09: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:09: Error: Failed to load FFmpeg libraries.
14:14:09: Trying to load FFmpeg libraries from system paths. File name is 'avformat-55.dll'.
14:14:09: Looking up PATH environment variable...
14:14:09: PATH = 'C:\Program Files (x86)\FFmpeg for Audacity;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps'
14:14:09: Checking that '' is in PATH...
14:14:09: FFmpeg directory is in PATH.
14:14:09: Checking for monolithic avformat from 'avformat-55.dll'.
14:14:09: Error: Failed to load shared library 'avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:09: Loading avutil from ''.
14:14:09: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:09: Loading avcodec from ''.
14:14:09: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:14:09: Loading avformat from 'avformat-55.dll'.
14:14:09: Error: Failed to load shared library 'avformat-55.dll' (error 127: The specified procedure could not be found.)
14:14:09: Error: Failed to load FFmpeg libraries.
14:14:09: Error: Failed to find compatible FFmpeg libraries.
14:14:14: Using internal LAME

Does the occurrence of this problem coincide with Windows 10 2004 update?

Have you installed any new apps recently?

This is what I get with Audacity 2.4.2 and FFmpeg 2.2.2

19:41:31: Audacity 2.4.2
19:41:31: Trying to load FFmpeg libraries...
19:41:31: Trying to load FFmpeg libraries from default path, 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
19:41:31: Looking up PATH environment variable...
19:41:31: PATH = 'C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Users\steve\AppData\Local\Microsoft\WindowsApps;'
19:41:31: Checking that 'C:\Program Files (x86)\FFmpeg for Audacity' is in PATH...
19:41:31: Warning: FFmpeg directory 'C:\Program Files (x86)\FFmpeg for Audacity' is not in PATH.
19:41:31: Temporarily prepending ';C:\Program Files (x86)\FFmpeg for Audacity' to PATH...
19:41:31: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
19:41:34: Error: Couldn't find symbol 'avutil_version' in a dynamic library (error 127: The specified procedure could not be found.)
19:41:34: Error: Couldn't find symbol 'avcodec_version' in a dynamic library (error 127: The specified procedure could not be found.)
19:41:34: avformat not monolithic
19:41:34: Loading avutil from 'avutil-52.dll'.
19:41:34: Loading avcodec from 'avcodec-55.dll'.
19:41:34: Loading avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
19:41:34: Returning PATH to previous setting...
19:41:34: Actual avutil path C:\Program Files (x86)\FFmpeg for Audacity\avutil-52.dll
19:41:34: Actual avcodec path C:\Program Files (x86)\FFmpeg for Audacity\avcodec-55.dll
19:41:34: Actual avformat path C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll
19:41:34: Importing symbols...
19:41:34: All symbols loaded successfully. Initializing the library.
19:41:35: Retrieving FFmpeg library version numbers:
19:41:35:    AVCodec version 0x373466 - 55.52.102 (built against 0x373466 - 55.52.102)
19:41:35:    AVFormat version 0x372164 - 55.33.100 (built against 0x372164 - 55.33.100)
19:41:35:    AVUtil version 0x344264 - 52.66.100 (built against 0x344264 - 52.66.100)
19:41:35: FFmpeg libraries loaded successfully.

Note particularly this part:

19:41:31: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
19:41:34: Error: Couldn't find symbol 'avutil_version' in a dynamic library (error 127: The specified procedure could not be found.)
19:41:34: Error: Couldn't find symbol 'avcodec_version' in a dynamic library (error 127: The specified procedure could not be found.)
19:41:34: avformat not monolithic
19:41:34: Loading avutil from 'avutil-52.dll'.

and this is the equivalent part from your log:

14:13:50: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
14:13:51: Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)
14:13:51: Loading avutil from ''.
14:13:51: Error: Failed to load shared library '.dll' (error 126: The specified module could not be found.)
14:13:51: Loading avcodec from ''.

It looks to me like Audacity may be finding a different version of FFmpeg on your system (a “monolithic” version) that is not compatible with Audacity.

In particular, this line makes no sense:

14:13:51: Loading avutil from ''.

Notice that before the final dot, that is two single quotes (not a double quote) :confused:

I have tried using the zip version of FFmpeg for Audacity.

Just so we’re clear, did you try running the installer first?

I’ve never had trouble with simply downloading and running ffmpeg-win-2.2.2.exe. And, just within the last couple of weeks I installed it on two new Win10 64 computers.

You might need to delete what you have or “hide” the old/existing files by moving them or re-naming the folder.

@DVDdoug: Yes, my default is the installer. It was working fine. Then something changed. I tried reinstalling using the installer and I also tried the zip file. I have deleted the extracted FFmpeg folder. Neither work. I have never had trouble with FFmpeg for Audacity until now.

@steve: No, this occurred with Windows 1909. The last program I added that could have impacted it was MPC-HC. I uninstalled it, but that did not help. I have searched my system, and everything else that uses FFmpeg DLLs is part of our system image and has been in use for two years. Those programs are periodically updated. I have tried temporarily renaming all other versions of FFmpeg, I could find on my system. I still get the same result.

I still do not get why my Audacity cannot load the shared library where yours says it could not find the symbol. At least it identifies the target file in the path string on my system. Mine says

Error: Failed to load shared library 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll' (error 127: The specified procedure could not be found.)

where your says

19:41:34: Error: Couldn't find symbol 'avutil_version' in a dynamic library (error 127: The specified procedure could not be found.)
19:41:34: Error: Couldn't find symbol 'avcodec_version' in a dynamic library (error 127: The specified procedure could not be found.)

And as you said, it makes no sense that the filename string on my system is empty.

14:13:51: Loading avutil from ''.

The necessary files are in the default install directory (C:\Program Files (x86)\FFmpeg for Audacity) and it does not help if I manually locate them, but Audacity seems to point to the proper directory. I can see the entry points in the DLLs, so they seem to be valid, and I have tried hiding or uninstalling anything I could find that might conflict. I’ve been through the registry, but I do not see any obvious problems. I am sure it something weird that has changed with my system, but this one has me stumped. I really appreciate the help, if anyone has any more ideas I will certainly try them. I’m still poking around trying to find what is causing this issue.

Do you have any security products installed that could be interfering?

If you don’t already have a work-around, try converting/extracting the audio to WAV or FLAC with [u]TAudioConverter[/u] or [u]Kabuu Audio Converter[/u].

We use CrowdStrike, but I do not have any control over that. I just tried copying the DLL and EXE files from ffmpeg-win-2.2.2.zip to C:\Program Files (x86)\Audacity and that seems to work. I see the version numbers under Preferences\Libraries and I can import a MP4 file.

audacity.cfg says it is pointing

[FFmpeg]
Enabled=1
FFmpegLibPath=C:\\Program Files (x86)\\FFmpeg for Audacity\\avformat-55.dll

and the log shows:

11:48:19: Audacity 2.4.2
11:48:19: Trying to load FFmpeg libraries...
11:48:19: mLibAVFormatPath ('C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll') is not empty. Loading from it.
11:48:19: Looking up PATH environment variable...
11:48:19: PATH = 'C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\dotnet\;C:\Program Files\Microsoft SQL Server\130\Tools\Binn\;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\;C:\Program Files (x86)\Windows Kits\10\Microsoft Application Virtualization\Sequencer\;c:\tools\gs;C:\Program Files (x86)\Brackets\command;C:\Users\<username>\AppData\Local\Microsoft\WindowsApps;C:\Users\<username>\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\<username>\AppData\Local\atom\bin;%USERPROFILE%\AppData\Local\Microsoft\WindowsApps;'
11:48:19: Checking that 'C:\Program Files (x86)\FFmpeg for Audacity' is in PATH...
11:48:19: Warning: FFmpeg directory 'C:\Program Files (x86)\FFmpeg for Audacity' is not in PATH.
11:48:19: Temporarily prepending ';C:\Program Files (x86)\FFmpeg for Audacity' to PATH...
11:48:19: Checking for monolithic avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
11:48:19: Error: Couldn't find symbol 'avutil_version' in a dynamic library (error 127: The specified procedure could not be found.)
11:48:19: Error: Couldn't find symbol 'avcodec_version' in a dynamic library (error 127: The specified procedure could not be found.)
11:48:19: avformat not monolithic
11:48:19: Loading avutil from 'avutil-52.dll'.
11:48:19: Loading avcodec from 'avcodec-55.dll'.
11:48:19: Loading avformat from 'C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll'.
11:48:19: Returning PATH to previous setting...
11:48:19: Actual avutil path C:\Program Files (x86)\Audacity\avutil-52.dll
11:48:19: Actual avcodec path C:\Program Files (x86)\Audacity\avcodec-55.dll
11:48:19: Actual avformat path C:\Program Files (x86)\FFmpeg for Audacity\avformat-55.dll
11:48:19: Importing symbols...
11:48:19: All symbols loaded successfully. Initializing the library.
11:48:19: Retrieving FFmpeg library version numbers:
11:48:19:    AVCodec version 0x373466 - 55.52.102 (built against 0x373466 - 55.52.102)
11:48:19:    AVFormat version 0x372164 - 55.33.100 (built against 0x372164 - 55.33.100)
11:48:19:    AVUtil version 0x344264 - 52.66.100 (built against 0x344264 - 52.66.100)
11:48:19: FFmpeg libraries loaded successfully.

Does that tell you anything? At least it is a workaround.

Super. There’s nothing wrong with doing it that way.

Work computer / school computer?
I suspect that some sort of security setting was getting in the way.

It is a work computer. FFmpeg for Audacity still works as expected on other computers I looked at. Security settings are global, so it is more likely something broken on my system. For the time being, I happy for the workaround. If I ever figure out the underlying cause, I will report back to help others who might experience the same issue. A big thanks to both of you for working through this with me. I know what a pain remote troubleshooting is.

Not that it would cause a problem, but your PATH is about 200 characters longer than mine…