2020 has no interaction whatsoever with the 2019 software - there are totally separate and do not share any files.
The problem that some users have with the Amazon download is that it is the Oct 2020 build that does not contain the latest updates. I understand that there was a bug in the Apple supplied C++ compiler that mangled a certain instruction that is causing extremely slow operation on some Macs that make it near impossible to apply the update that fixes the problem. Current downloads from TurboTax (not Amazon) contain the fix. If you are not affected then it makes no difference to you.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
