In most cases, this is the result of a CPU overload. You could deactivate a number of tracks to see if this solves the situation - if so you may find a limit of tracks that will work without overloading the CPU.NOTE:It is possible to reduce the CPU load of B4 HTDM. By reducing the number of tones in B4's polyphony menu you can do so more or less without loosing sound quality.... you may hear a difference but it is not too annoying in most cases. This settings reduces the maximum number of virtual tonewheels which saves CPU time.