I have downloaded 2021 pro series but when trying to transfer last year files they do not appear for transfer, why?

[Just-Lisa-Now-]

when you're in the transfer window, make sure the folder (transfer files from) showing up in the left corner of the window is where your prior years data files are stored.

[dkh]

Check your file for Transfer data files from       is it correct?

[Jim-from-Ohio]

I think most people here wait until they transfer files for a bit for a more up to date version as there have been problems transferring files too early in the past. 

[jeffmcpa2010]

"I think most people here wait until they transfer files for a bit "

That may be, but Transferring files does work now on my setup. And anyone who sends out organizers to their clients likely wants to transfer the files to the Organizer homebase early so they can get started on printing them and getting ready to mail.