I printed my tax forms to mail, but I changed my mind and want to e-file instead. However, the site no longer lets me access my forms. How can I access the forms?

You can try to switch to efile.   Click on Add a State to let you back into your retun.

  https://ttlc.intuit.com/community/e-file/help/how-do-i-change-from-mail-to-e-file-in-turbotax-online/00/26985

Thanks so much for responding.  It worked!  I tried lots of other approaches without success.  What a bizarre solution.