Although you can run the program from the copy made to the external drive, that is possible because you first installed the program to your internal drive. Needed fonts were written to Windows, and there may be a few other things like that. So, I would not uninstall the program from the hard drive; I would just delete the /BB folder. As mentioned, this is only if you need the space.

Don't forget that most of the space taken by the BIAB program is for the RealTracks and, to a much lesser extent, RealDrums. That's why BIAB allows you to place just those on another drive. This is what I have done. It greatly reduces the footprint of the program on my internal drive, but functions perfectly.

BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus 192 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.