MuseScore (4.0.0.223472200 rev 5485621) task disappears (crashes?) when trying to open an almost empty sheet

1. Create a new sheet with the + symbol (32 bars, 5 instruments), filling in title etc.
2. Moving "Voice" to top of instruments, and renaming it to "Solo"
3. Hiding all but "Voice" instruments
4. Struggling back and forth with how to enter short pauses (1/16 etc) in first bar (I am beginner)
5. Although unknown when and why, I apparantley by mistake made Bass voice visible again along the road
6. Saving sheet, closing app, restarting app (works so far)
7. When trying to open sheet again, task disappears (crashes?). No musescore message at all.
8. Trying many times without success. Perhaps too early to use version 4? But the very first simple sheet I made however still possible to open (stored in the same location).

I attach the sheet file that I cannot open.

I can start from scratch with this sheet again, but feel reluctant about the app because of fears that my work suddenly becomes unusable.

Windows 11, 16 Gb Ram, Avast-one Free antivirus, sheet file stored in windows user folder
Unable to specify version 4 above (is version 4 for test only yet?) Adams Julsång (Helga Natt).mscz