If you saved the 2015 tax return using the 2015 desktop editions the tax data file would be on the local drive of the computer where the return was saved. The 2015 tax data file has a file extension of .tax2015 and is normally located in Documents and in the TurboTax folder on a Windows based personal computer. If you upgraded the OS on your computer recently to Win 10 the upgrade may have moved the data file to somewhere else on the local drive or to the Recycle Bin. If the tax data file is not in the TurboTax folder then do a Search of the local drives for the file.
