Just a quick question, are you running any plugins? I was having a lot of crashes and hang-ups on V11.20b2 until I deinstalled a certain plugin. Don't just disable them, remove them one at a time, if you have any. Then see if that helps.
A clean install may be necessary. They are not fun but sometimes necessary to resolve strange problems. After adding, modifying, and deleting files, who knows what state things are in.
Good luck with your troubleshooting.