I use rendering quite a lot as a checking tool and I've found that with 2008, it's quite quirky. My previous version used to read that it went to 100% in the render process, in 2008, quite often it only goes to 50%, yet still does the full render. Probably at least 50% of the time when I go to Cancel the render (because I've already seen a mistake and don't want to go through the whole render process), render goes into freeze mode and sits still for ages. The Cancel button disappears and initially when it was frozen for such a long time, the only thing I could do was shut down Revit and start again as no buttons were operative. This often meant lost settings if I hadn't done a save immediately before starting rendering. It also meant a lot of lost time and even more worrying - more lost hair and splintering of teeth.
I've since found that after a period of slumber, the render will move to completion, but it's very frustrating when the machine controls things and I can't.
Is this a bug in 2008, as I didn't seem to have a problem like this with 9.1? If so, is this likely to be fixed soon? If not, does anyone have any hints on how to resolve this?