Cannot Open Or Start AVI Movie File? There seem to be a few people encountering this problem since I've found no answers online. I just rendered an animation but I need to render it again as the keyframes didn't match up properly because of the lag. I haven't changed any settings or anything since my last render (I think). Has anyone else encountered this problem/know the solution? 

Thanks!
I was really stumped when I switched operating systems, reinstalled Blender and suddenly my animations would no longer render. Turns out my Output path wasn't writeable in the new operating system. Perhaps it's unlikely your issue ends up being so simple, but since I stumped me for a bit, I thought I'd post my solution here and hope it helps someone else.