My audio file was working just fine until I split a stereo track into mono and then deleted one of the tracks I didn’t need and saved the file. And then boom I can’t open the file anymore. I was using audacity version 3.0.2. I’ve already tried updating to the latest version. I think I recall audacity saying something about my disk not having enough space.
Audacity 3.4.2 is the generally accepted stable version of Audacity.
Running out of space on your drive is pretty common. Audacity saves multiple versions of the show as you edit and it’s easy to run out. If you do, that’s the end of the world.
External drives are not recommended with Audacity. Do Not use cloud drives.
Did you keep a safety protection copy of the original show? Export a Perfect-Quality WAV file of the show before you start working on it. Audacity Projects are actually very slightly higher quality, but as you are finding, they can be brittle and easily damaged.
You can save shows and production files wherever you want, but you just can’t let Audacity see you do it. It really likes doing active production on the internal drive.