PS: I also think I found out what caused the SGU file "corruption"... which may or may not be a true corruption. I had NOT created a Performance Audio track, but I DID have WAV files I had exported from the SGU into the same folder as the SGU. Just now I read this from the SteelGuitarForum.com (see below in quotes). So... I ended up deleting EVERYTHING from the folder except for the SGU file. Voila. No more corruption. BIAB is a weird weird program sometimes.

"Yes you can share Band-in-a-Box SGU and MGU files.

If you are sharing files with other users it's possible someone may not have a RealTracks. There is still a way to share the track. The feature is called "Performance track".

Performance track saves a track as an audio file. You can send a Performance track audio file to your friend who will be able to play that track in a Band-in-a-Box song file without needing to have the RealTracks installed. Performance track radio button turn orange when the track is saved as a Performance track. The track patch name will be orange when the Performance track is loaded.

One way to save a track as a Performance track is to right click on the track patch name, navigate to "Track Actions" and select "Save track as Performance file (wav/wma)" then select wave or wma file format.

The audio file will be named as whatever is the name of the song and the track. The audio file is saved in the bb folder.

Any audio file can be a Performance track in Band-in-a-Box as long as the audio file title includes the name of the loaded song file and a track and the file is stored in the same folder as the song file."