I had the same issue as the above, and your fix worked for me! I installed on a Windows 7 machine and learned that the product support would not be there next year. I prepared 2 tax files in Deluxe version and then decided to get a Windows 10 machine. Downloaded Deluxe with my license key and installed. Updated and then transferred my .tax2019 files so that I could continue my returns. Couldn't open the file, wouldn't get an error message just wouldn't open.
I called TurboTax product support and after explaining and explaining my issue I was finally just told that my files were probably corrupted and I should have "Copy" not "Move" my files to my new machine, as I was wiping my data from my old machine. She told me to delete the files and then "Copy" again. I told her I couldn't COPY if they were MOVED in the first place - the files aren't there anymore. I was also told when trying to open the .tax2019 from the Browse/Open menu to "Save As" first... when the only dialogue options were "OPEN or CANCEL". Long story short, I hung up wondering why I wasted 20 minutes of my life on the phone, searched here and found the first link helpful.
Bottom line is - EVERYONE at TurboTax product support should be aware of this workaround as they state there is no knowledgebase article regarding this error and they have no workaround. Once I added my State Product (I thought I already did) then I had no problem opening my file.
Product support should never be this helpless, as this is an easy fix!
