MuseScore 4 eating my scores

Hello all,

I was recently scoring a marimba solo in MuseScore 4 and saved and closed it. I accidentally opened that solo and a few other songs in MuseScore 3 because it is still the default program to open .mscz files on my computer. Upon trying to open the score back in MU4, it says the file is corrupted. I tried to follow the directions at https://musescore.org/en/node/335842 to fix the affected scores, but my computer says that the files contain no data, and are shown as "Size 0KB" under file manager. The error report in MU4 also says that the scores contain no data.

I would like to recover these scores because I have put a good deal of work into them. This issue continues to happen, along with other MuseScore 4 sync bugs that never seem to resolve. This is embarrassing that MuseScore 4 is out of beta, until this gets fixed, MuseScore 2 will remain my favorite version.

Thanks for any assistance.