I somehow got it to work after having this issue, but I'm not entirely sure how I got it. It may have just been me trying multiple times and it finally went through as perhaps it was some server issue on Turbotax's side. But here are the steps I tried that will hopefully help everyone recreate this.
-Uninstall it.
-Right-click the installer and run it as administrator. Then install as usual.
(The above two I think are the main things I did differently than everyone else here.)
-Add an exception to the .exe file in Windows Defender in the "virus & threat protection" and "firewall & network" protection settings. (or equivalent antivirus) It should be located at "C:\Program Files\TurboTax\Individual 2024\64bit\TurboTax.exe" by default or something that looks very similar. You can find the path by right-clicking the desktop shortcut icon, clicking "properties", then the "shortcut tab" and finally checking the "target" box to see for sure.
-Instead of double clicking the desktop shortcut icon to run it, right-click it and run this as administrator too.
From there it worked and I was able to reach the product key entering step.
But what a pain this was. It seems like every year there's some new issue to contend with and they don't tend to fix bugs from prior years too. So they just keep stacking up.
