My BiaB saves with mutes too.

So I did a detailed testing this morning of the VSTi plug. If I keep the number of bars at 12, and the multiriff bars at 4 to 6 max I get a render of around 1:30 I can add a second drum track below the melody and solo tracks, but it changes the name of the track to one of the tracks above but does generate a drum track.

If I go above around 18 bars or more than 6 bars of multiriff I get a slow down and a Range check error and I lose the yellow note banner.

I hope this has the techs to locate the problem.

HP Win 11 12 gig ram, Mac mini with 16 gig of ram, BiaB 2025, Realband, Reaper 7, Harrison Mixbus 9 32c , Melodyne 5 editor, Presonus Audiobox 1818VSL, Presonus control app.