Mid score key sig change causes all saves to become unusable, no error message, MS3 hangs.
This is in the Beta. I had (have?) a piece that changed key signatures in the middle. There is some odd behavior that happened when I placed the key change - apparently it was local instead of global as I intended - but no indication of an actual showstopping problem.
But after that, none of my saves would open, autosave included. MS3 beta would hang, there were still no errors. In fact, since I had the 'Continue last session' program start preference, MS3 refused to start - it wouldn't even pull up the splash screen. I had to nuke both Local appData and Musescore3 docs (Yes, win 10) to even get it to boot again.
After some research, we found the key sig to be the problem - I had plenty of work done, it was hard to pinpoint. I'm attaching the unworking auto save, and the much earlier hidden file that does work. It has the original key change I attempted to make global in the Contrabass. I later found out it wasn't global when going through the Cello and Viola - staves are hidden - and when I tried to fix it, that's when the save file became unusable, I believe.
reference thread: https://musescore.org/en/node/279010