The hiq_instruments_sforzando.exe (you need to run this to register the library) lets you choose the location
and the playable_realtracks0x_sforzando.exe lets you choose that same location
the default is
C:\Program Files\PG Music Inc\Band-in-a-Box Sounds\
you should be able to change it to d:\Band-in-a-Box Sounds\

Else you can create a symbolic link for the folder
C:\Program Files\PG Music Inc\Band-in-a-Box Sounds\Programs\Playable RealTracks
and move the actual Playable RealTracks folder to d:

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BB-SFZ-Library-Location.png (11.91 KB, 139 downloads)
BB-PRT-Library-Location.png (12.63 KB, 139 downloads)