I have the same problem - 2014 iMac with Big Sur wont load TT2023 that I paid for. Not the first time TT has let me down like this. A couple of years ago I was halfway through my return when Apple pushed an update and I couldnt finish up on time. I'm not tossing a perfectly good Mac for TT. It's not clear to me if I could use my license to pay for the online version, but from what I read it's has some significant disadvatages compared to the download version. Looking at other options.
