"Forcing" the animation with mouse -is it bad?

Not much to it, really, as pretty much all evaluations in AE are triggered by a change of time event, typically comp time and that always uses the last valid time, meaning anything that might "burden" AE will simply be skipped over or be swallowed by the processor not finishing its computing cycles. The worst that can happen on slower systems is that your harddrives cannot keep up with footage and cache file I/O or your graphics card crashes if some realtime function is too much of a strain on your PCI bus. The rest is just AE being what it is and the plethora of bugs it has. So if there is any data corruption, crashes or even physical damage, it's more likely bad code than just AE's basic paradigms causing mayhem.

Mylenium