I had completed a Federal return for 2019, but did not yet file it. When I logged in today, TurboTax online acts like I am starting over. Dude...Where's my data???

You have to sign onto your 2019 online account using the exact same user ID you used to create the online account.

Close all TurboTax windows on your web browser (including this one).  Copy and paste the account recovery website link onto a new web browser window and run the tool.

Use this TurboTax account recovery website to get a list of all the user ID's for an email address.  Run the tool against any email addresses you may have used - https://myturbotax.intuit.com/account-recovery

If none of the user ID's received will access your 2019 account, then use the option shown in blue on the account recovery website, "

Try something else

If you used the desktop CD/Download editions installed on your computer, the only copy of your tax data file and any PDF's will be on the computer where the return was created.  TurboTax does not store online any returns completed using the desktop editions.

To access your current or prior year tax returns sign onto the TurboTax website with the userID you used to create the account - https://myturbotax.intuit.com/

Many people have multiple TT accounts and forget how to access them.  Log out of the account you are in now.

Account recovery

https://myturbotax.intuit.com/account-recovery/

https://ttlc.intuit.com/questions/1901535-forgot-your-turbotax-online-user-id-or-password

Or did you use the desktop version of TurboTax?  If so, the files are on your own hard drive or any backup device you used like a flash drive.

https://ttlc.intuit.com/questions/1901486-how-many-turbotax-accounts-do-i-have

https://ttlc.intuit.com/questions/1901535

You have to sign onto your online account using the exact same user ID you used to create the account.

Close all TurboTax windows on your web browser (including this one).  Copy and paste the account recovery website link onto a new web browser window and run the tool.

Use this TurboTax account recovery website to get a list of all the user ID's for an email address.  Run the tool against any email addresses you may have used - https://myturbotax.intuit.com/account-recovery

If none of the user ID's received will access your account, then use the option shown in blue on the account recovery website, "Try something else"

If you used the desktop CD/Download editions installed on your computer, the only copy of your tax data file and any PDF's will be on the computer where the return was created.  TurboTax does not store online any returns completed using the desktop editions.

First - I am impressed at how quickly I got responses.  Just after I had posted, I was looking on my local drive to see if I had saved my return, and discovered a current file from the desktop version! I had forgotten that in late January when I had problems with the online version, technical support had me switch to desktop!

What a relief!