I just installed Audacity 2.3.0 this evening on my Windows 10 (Home) machine.
I downloaded avformat-55.dll from the Internet and placed it in the following folder, which I made:
C:\Program Files (x86)\Audacity\FFmpeg
I re-started Audacity and went into Edit/Preferences/Libraries to tell the program where avformat-55.dll is located.
All of this effort has had no effect.
Audacity will still not import m4a files.
What is the solution to this problem?
I have seen several threads on this topic, none of which post a solution.
It is extremely dangerous to download DLL files from the Internet. DLLs provide one of the easiest ways to infect Windows computers with viruses or other malware.