Are you trying to run the program or install it? I don't think you can run Turbo Tax from an external drive. It has to be installed on the computer. Maybe this will help?
I found this article, Reinstall Turbo Tax for Windows 8.1/10/11.
https://ttlc.intuit.com/turbotax-support/en-us/help-article/reinstall-products/reinstall-turbotax-wi...
