Error 102346 can occur when attempting to open a file type that is not supported in TurboTax for Windows (like a PDF file).
Solution
TurboTax for Windows can only open files with a .tax20XX file name extension, where XX is the 2-digit tax year specific to that TurboTax version (for example, a .tax2020 file can be opened in TurboTax 2020, but you'll get an error if you attempt to open the .tax2019 file in the 2020 TurboTax program).
To open a PDF file, use Adobe Reader instead of TurboTax.