I was able to get 2020 installed and filed, however, the software kept referring to an error (1) and would not let me override to file electronically. I do believe that TT should allow and insure that the user understands that they are overriding the software, but allow it to transmit and file. (My situation was a K-1 with an entry that the software didn't like).
As to TT 2021, I did purchase and had not problem installing or registering.
Jim
