@user17715921857 It just started working correctly for Fidelity yesterday. Prior to that, I was still being required to delete the previous import's data before continuing. But, seeing a 1099-B form on the list, the new "Upgrade to Premier" warning reared its ugly head.
So I am imagining that the "Delete old data" warning is institution-specific, and still in place for many financial institutions. Once you identify the institution you want to import from, there would have to be a block of code that is unique to that institution, since the graphics differ as well as the messages informing you that some firms' forms are not yet ready for download. Only when the 1099 forms are pulled in to your tax file are you then handed back to the TT program. Thus I think they will have to fix this issue for every single import partner.
@MarilynG1 Although a fix appears to be in for Fidelity, it sure would be nice if TT would communicate what is going on with respect to fixing the "Delete Old Data" issue for others who aren't so lucky.
