mute and corrupted files

I have saved a bunch of files for a piece of music I was writing. I have put at least 20 hours into it, and now it is corrupted and cannot be opened. I am super frustrated at this. This was on musescore 4, and I might go back to musescore 3 for its lagginess. Additionally, the mutes don't do anything, and the purcussion instrument does not use musesounds. I would love for issues and little quirks like this to be fixed. Thanks!