After Effects keep crashing the final render when using rotobrush 2

Impossible to know much without actual crash info and exact system info, but you likely pretty much answered your own question: You need to straighten out your graphics driver and settings so GPU acceleration works smoothly. Other than that of course there could be any number of otehr issues with caches or simply running out of disk space, be it just for temp files during render. in any case, not much point to speculate on such vague info. You have to be much more specific. Start by checking the things I mentioned in passing, then come back with better info if it still doesn't work.

Mylenium