If you saved your tax return while doing your taxes in the CD/download edition of TurboTax, all the information in your return is stored in the TurboTax data file. (Note that this is different from the PDF copy of your tax return that you usually save after filing your taxes.)
By default, TurboTax saves your tax data files in the Documents folder on your computer. The specific folder location is
C:\Users\<user_name>\Documents\TurboTax\<YYYY>, where <user_name> is your Windows user name and <YYYY> represents the tax year. For example, John Doe's Windows user name is jdoe and he's looking for his 2018 tax return. If he saved his tax return to the default location, it got saved at
Possible reasons why you aren't able to find your tax data file
TurboTax saves the tax data files to the Documents folder under the profile of the user who is logged in during the tax preparation. If you have a computer with multiple user accounts, you might not be able to access the folders or files stored under the other accounts. For example, John and his partner Jane share a computer. There are two accounts on their computer, one named John and the other named Jane. If John logs in to the computer using his account, he might not be able to access files that were saved when Jane was logged in.
So, to find the tax data files, you need to log in to Windows using the same user account that you used when doing your taxes. Using the previous example, when doing their taxes, John and Jane were logged in to their computer using Jane's account. Now, if John logs in to the computer using his account, he might not be able to find or access the tax data file (John&Jane.tt18). He needs to log in to Jane's account, or have Jane log in to her account, and then go to C:\Users\jane\Documents\TurboTax\2018 to locate the file.
During certain types of Windows upgrades, you might be required to do a clean install, which involves a complete formatting of your hard drive. If this is the case, your TurboTax data files might got deleted from you computer, but could still be accessed if you backed them up to an external drive.
While you are doing your taxes, TurboTax prompts you multiple times to save your tax data file. Although unlikely, it is possible that the tax data file was never saved. Power failures and program crashes are examples of situations when this could happen.