There is a "clear and start over" feature in TurboTax online. See the information below:
https://ttlc.intuit.com/replies/4248526
Does anyone actually read the questions? The return was finalized, cannot clear and start over
Yes, we are here. The answer is how to clear the Online version which you said you didn't use since you used the Desktop program to file instead. You said you wanted the Online version purged which is the same as clearing it.
Right, did you read the first line -- The return was finalized. Cannot purge using your instructions.
If you paid the fee and registered, TurboTax is required to keep a copy of the return on file. See the additional information above.
Did you pay for the Online version or register it? Well anyway if you can't clear it just ignore it. Nothing will happen. You can't delete accounts. Just remember next year to transfer from the actual filed return that's on your computer. So if you use the online version either set up a new account or don't transfer from online.