What kind of files are you looking for? If you are looking for tax returns that you filed, did you file them with TurboTax Online or with the desktop TurboTax software installed on your computer from a download or a CD? If you used the desktop software, did you use it in Windows or on a Mac? If you are looking for something other than tax returns, what exactly are you looking for?
Did you use desktop software on a Mac? When you save the return on a Mac, one of the choices offered to you is to save the file as an encrypted file---which means you better know what password you invented to access that file again. You do not *have* to encrypt the file---but if you made that choice and forgot the password, that is a problem.