Version 2.1 won't load load at all, crashes during loading.

Version 2.1, on Windows 10 with all the latest security patches (it started happening after the latest "upgrade" to Windows 10, about a week ago. Possibly related to a file with Virtual Playing Orchestra SFZ files that were left open upon the close of the program last time it was working? The first time it happens, the opening of the program gets as far as opening the "windows" of the program without any contents. At that point I get the "Musescore.exe has stopped working" (A problem caused the program to stop working correctly. etc.)" with the choice to close the program. If I try to open the program a 2nd or 3rd time, It usually crashes immediately, before anything happens at all. In other words, the "Musescore.exe has stopped working" dialog box pops up before anything happens. I have done the following: 1) uninstalled and reinstalled the program several times 2) run a registry cleaning program, 3) run regedit myself, and found several instances where there were references to Musescore 2.0 and removed those.
Interestingly, I still have a "nightly" version (fee488e) that is still working on my computer, thank goodness!! But they both were working for a month or so since 2.1 came out until a week ago. I hate to blame Windows 10's upgrade, but I don't know what else it could be.
I looked for application crash logs, but the only logs I have are from 5/8/2017 and before and are now stored under a windows.old/ folder