I've tried the short repair, which didn't help, and the online repair twice. Both times the online repair failed with the message Something went wrong, with Error Code 30010-4. Both times, that left my system without Office installed, so I reinstalled Office. I still have the same problem.



I can open the encrypted files on my old Win XP, Word 2007 system, and my Android phone, but Word 365 on Win 10 still crashes when I try to open the files.



I can create a new Word file, password protect it, save and close it in 365, but when I try to reopen it, Word 365 still crashes. The other systems will open the new file.

I also see you are responding to a similar issue on the Microsoft Support pages, and tried your sfc /scannow suggestion, but it did not find any integrity violations.