This error can be produced by opening a non-tax file in TurboTax (for example, a PDF copy of a return) or a tax file from a previous version of TurboTax. TurboTax 2021 will only open .tax2021 files. If you experience this error while trying to open a TurboTax file, ensure TurboTax is up to date by selecting Check for Updates from the Online menu.
In some cases, this error may be due to file corruption. If so, the file may be unopenable. In this instance, you may need to start over if you're unable to locate a backup file.
If a backup file exists, it'll be in the same directory where your original TurboTax file is saved. The file will be named the same as your normal TurboTax return but with a tilde (~) in front of the file name and may be hidden. You open this file by selecting the File menu in TurboTax, and choosing Open a Tax Return. Navigate to the directory where your other tax file is located and select the return with the tilde in front, and then select Open.
