These messages may appear immediately after installation or after an update to Audacity or Windows.
You likely discovered the name "avformat-55.dll" when you tried to import a video file or an M4A track and were met with an error message. To fix it, you need to install the FFmpeg Import/Export Library specifically built for Audacity. How to Install it Safely Avformat-55.dll - Windows - Audacity Forum
, a set of tools that allows Audacity to read and write these complex files. audacity avformat-55.dll
If the DLL exists but is not in a directory Windows recognizes (or the Audacity Plug-Ins folder), the software cannot see it.
You might encounter any of the following variations: These messages may appear immediately after installation or
The 55 in the filename refers to a specific version of FFmpeg’s libavformat library (version 55). Different Audacity builds might use slightly different numbers. This one became common during Audacity’s 2.3.x and 2.4.x era. It’s like a translator with a particular accent — version 55 has its own quirks and supported codecs.
Bookmark this guide, share it with fellow Audacity users, and keep your audio projects moving forward. How to Install it Safely Avformat-55
Invalid or broken Windows registry entries linked to FFmpeg can prevent the DLL from loading.
For Audacity 3.x, the official installer often includes an FFmpeg option during installation. Re-run the Audacity installer and check “Install FFmpeg.”