@parpilot
Just a couple things I think of, but only if you are on a Windows computer:
1) a couple new Windows updates were released this week. Waiting Windows updates are known to block installation of TTX. Fully run those updates and reboot (I recommend reboot twice).
2) When retrying the installation, rt-click on the installation file and select "Run as Administrator" (Normally shouldn't be needed, but sometimes helps).
3) if Windows 11, make sure you have the most recent versions of Microsoft Visual C++ installed . the x64 version:
Latest supported Visual C++ Redistributable downloads | Microsoft Learn
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*