Encountered the same issue on my MacBookPro MacOS Big Sur Version 11.3 Beta (20E5172i) running TurboTax Basic 2020 app ver 2020.r16.037.
Had already completed and successfully filed my Federal Tax 2020 Return electronically a few days before, took the latest update, and tried to check my E-File Status. After checking, I closed TurboTax and a day later tried to launch to check E-File Status again. That's when I started getting the crashes upon launch of TurboTax.
I too spent many hours trying to track the crash down, but because it happened upon launch there was no way to really track what was going on, and also could not save a crash report to send off to TurboTax tech support.
However, when searching with Google I found the comments from pvanamst to be most useful. Following the instructions in Step 2 (deleting all files under ~/Library/Caches/KSCrash/TurboTax) resolved the issue. I was able to then launch TurboTax Basic 2020 without crashing.
THANK YOU pvanamst for your research and posting your resolution to the crash issue. Most appreciative!
