Why am I receiving corrupt file messages for my PC based 2020 program?

I couldn't transfer from my 2019 e-filed return, despite following directions received here.  So I started a new return from scratch.  It is almost finished, but when trying to access it I received a "file corrupted" message.  This is the second time this year  this has happened and it never happened before in all my years using Turbotax.  I hate to have to re-enter everything again.