I ran into the exact same problem and checked the events on the "unused" tracks (6 through 48). They all contain VolNodeCtrl and VolCtrl events. I didn't touch those tracks so I have no idea how they got there. This is preventing RB from generating tracks.

RB seems to get into this state simply by changing the style and choosing Generate All Tracks. I'm a noob so I might be doing something wrong.


BB+RB 2014 (3)
Windows 8 Pro 64-Bit