I hope you get the SD-50 working. It's one of the few Roland synths I didn't use, but the demos sounded great.

Sorry I didn't give more exact directions, as I was not in front of a BIAB computer at the time. You said you reinstalled BIAB to run from the external hard drive. I'm assuming that means you had previously installed BIAB to your internal drive. If so, what you selected in the new install from Setup.exe should have allowed you to specify where the RealTracks and RealDrums are. Even so, you can check, and if needed, change where they are:

Opt., Preferences, RealTracks.
Put a check in the box for "Use a Custom Folder Location for the RealTracks".
In the box directly below, type the path of the RealTracks (or use the file folder icon to locate it).
For example, mine says G:\bb\RealTracks\

Then do the same thing for Opt., Preferences, RealDrums.
For example, mine says G:\bb\Drums\


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.