HERE IS WHAT WORKED FOR ME. (This problem happened on one of my (Windows10) PC's but not the other.)
I ran a free program that repaired the permissions on my Program Files directories and Registry. The program is from Tweaking.com, the Windows Repair program (free). There a great youtube that explains how to run it. (Hint: You are looking for the "Presets: Permission Only" button.) Run it using the default settings, reboot, and (for me) the "Error 1603" installation problem stopped.
That might be enough. For me, after the above, I was worried that my original install might be messed up, so I...
- Uninstalled TurboTax2022
- Installed it again as Administrator (right-click on the install file and select "run as administrator")
- Ran TurboTax itself as Administrator (right-click, "run as administrator").
The initial update ran successfully, and after that, TurboTax ran perfectly every time.
I did not need to bring up SafeMode, turn off my virus software, etc.
(I then uninstalled Windows Repair - I no longer needed it.)
I hope this helps others.
