This answer was SO helpful! I had the same problem with TurboTax 2021 Premier for Mac running BigSur (11.6.4). TT was running fine (had even installed updated when I started a few days ago). But then crashed when I attempted to close a return after filing/printing one of my two returns. After that crash I couldn't start it. The process would run for a short time and flash a small screen for a second (something about verifying updates) and then the process would end. Reinstalling didn't help. I had to do your instructions to make sure all the hidden files associated with TurboTax2021 were deleted.
BTW I called customer support and they weren't able to help me. I made it to second level support and their solution was to use turbotax online. I didn't want to do that. I prefer download. So I dug in more and found your helpful article. Using Finder to find the hidden files was awful, so I used Terminal and did a big find/grep to get the list.
Thank you so very much!
