Yes, I found the same solution just now independently. After posting the question originally, I temporarily copied my 2023 tax file to my hard drive, and started this year's work. I did nothing more than verify the personal information, then saved and exited. I then copied the 2024 files (primary and autobackup) to my secure vault, and used BitDefender's shredder to remove all trace of my 2023 file from the hard disk.
This morning I started TurboTax, did its update, and before trying to see if it would read the fault (assuming it wouldn't), I exited the program and then double-clicked on the file in the vault. TT opened fine using that file.
Next I exited TT again, then started it from my Start button. It comes up with the Continue option, listing a tax file. I clicked "Continue", and despite the fact that the file is on the vault, it reopened the file.
Next I used File > Open, No saving (since I didn't make any changes this session), then clicked Find a Tax File, and it opened the explorer window inside my vault.
Finally, I exited the program completely, restarted it from the Start button, clicked the Find a Tax File option, which defaulted outside of my Vault. But I clicked on the link to my vault, and it very obligingly read the vault. I cancelled that, returning to the prmary program, and "Good News! We found your tax info", including the 2023 file for the second tax return I need to file.
Conclusion: On initial entry to the program: the Vault is Untrusted for whatever reason. But once the user clicks on a 2024 tax file inside the fault, the vault from that point forward seems to be Trusted.
Thanks for your assistance.
