I'm also having this problem, starting late last night and today. Running Big Sur 11.2 on a MacBook that's a few years old. TurboTax 2020 for Mac was working, I just got everything in, but now it's gone bye bye. I tried deleting the app and reinstalling it. Then, after checking other comments, I tried opening TurboTax 2019. It said it needed updates applied. Now it, too, also doesn't open. A small little notice pops up and disappears before I read it, but the app won't launch.
