The IRS and TurboTax save returns for 7 years. If you did not save them yourself as hard copies or pdfs, they are gone.
If you have used more than one account during the past seven years:
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
https://ttlc.intuit.com/questions/1901659-find-your-tax-data-file-in-mac
https://ttlc.intuit.com/questions/1900721-find-your-tax-data-file-tax-file-in-windows
To get a copy of your previously filed returns prepared with online TurboTax https://ttlc.intuit.com/questions/1900748-how-do-i-get-a-copy-of-a-return-i-filed-in-turbotax-online
This is an attempt to respond to the replies that I received for this question. I have tried several times using the suggested methods. Unbelievably TT insists that I used TT for the very first time last year. In previous years using the older website, I could easily find a previous tax return using every account that I had (two). Now it seems as though every attempt to do something requires me to sign in again with the 2 or more step confirmation with another brick wall. But thanks for the replies. BTW the above question had to be rephrased several times to get to the next baffling step.
TurboTax accounts cannot be combined, so one TT account does not "know" about another account you have. Thus, an account might say it is the first time you have used TT. Sorry---when you open multiple accounts it can lead to confusion especially if you have not kept yourself a record of the accounts and user ID's you used. Going forward, pick one and stick with the same account. If you use exactly the same account and user ID from one year to the next then you will be able to easily transfer data from one year to the next.