Audacity keeps losing avformat-55.dll

I’m trying to open some files that require avformat-55.dll. I follow the instructions on how to install it, I change nothing about the installation, I tell it to go to the default directory. It finds it then I when I’m done and close Audacity, I open it back up and get the prompt in the attached screenshot and I go into preferences like I’m told to, then I click Locate, it goes directly to the folder it’s in, I select it, and it still doesn’t find it. I have to redo everything multiple times before it will find it again. (I do both the exe and the zip folder) and I sometimes get it to work, and I close and reopen it as a test, it sometimes stays found but eventually that error will popup and have to fight with it to find it again. It’s never done this before until now.
Audacity avformat-55 error.png
log.txt (15.6 KB)

Do you have more than one version of Audacity installed?

Whoa somehow I do, weird, thought I uninstalled the last one. Let me check things out.

I think I somehow installed an old version on one drive and the newest one on a different drive. but the weird thing is, I’ve been doing projects it like this for awhile now, and I’ve never gotten this error before until now. But thank you, the problem seems to be fixed for now and I freed up some hard drive space.

I think I can guess what happened.
Normally when you install a new version of Audacity, it updates (overwrites as necessary) the old version.
However, the latest version of Audacity (3.0.4) is a 64-bit app, so by default it is installed in a different location from older versions.

64-bit Audacity requires 64-bit FFmpeg, and 32-bit Audacity requires 32-bit FFmpeg.
After updating to 64-bit Audacity 3.0.4, it is necessary to also update FFmpeg to the new 64-bit version (See: for details).

For others reading this that have not yet updated to Audacity 3.0.4, I would recommend uninstalling your old version before installing the new version.

In future this won’t be an issue because future Audacity releases will be 64-bit, so they will update the previous 64-bit version.