Autosave is a feature of online TurboTax. Were you using online? Maybe you are in the wrong account now if you cannot find the return you were working on.
Many people have multiple TT accounts and forget how to access them. Log out of the account you are in now.
Account Recovery
https://ttlc.intuit.com/questions/1901535-forgot-your-turbotax-online-user-id-or-password
https://ttlc.intuit.com/questions/1901486-how-many-turbotax-accounts-do-i-have
If you were using the CD/download you have to save it before you exit the program. With the CD/download the files are stored locally on your own hard drive. They are not stored online.
https://ttlc.intuit.com/questions/1901659-find-your-tax-data-file-in-mac
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/find-last-year-tax-data-file-...
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**