Oh well I use a program called Wintop I just check the processor usage.There is really no way to tell if it's stuck in a loop. you'd have to make calls right to the processor. check also that you don't got some damn stupid power saver thiny turned on cause your proccessor could be forced to idle and the drives going to sleep that could lock up Vue. I got mine set always on. I never turn my computer off ever and I just use a blank black screen saver. One thing to try is render the whole wad really small say 256 X 256 just to make sure everything is perfect before you attempt the bigger size. When Vue crashes the cpu power usage for that program drops to 0% then you know it's dead if it's up at 98% you know it's rendering. If it's less than 98% something else is sucking back cpu cycles (like say Vue reports 48%) find it and turn it off till the render is done. How I tell what's going on is I find the line on the screen where Vue is currently working then I place my cursor on it then later you can tell if it's done more more easily. Best is just no peeking till it's done. It will finnish. I've rendered 110 hour scenes. You just got to have patience. Make sure you got lots of free space on c drive so the ever expanding swap file will fit. Like lots of space, a few gigs free. That will kill you on a really long renders, the c drive filling completly killing vue in a out of memory error. You can just find that wintop program on a search on google.It's free of course. The antialasing pass is the worse cause it hardly updats at all then glow and glow antialasing it doesn't update any so it really starts to look like vue has crashed. Try to fix your scene, Group, man it will save you. I just rendered a scene with over 164 lights, easy. it worked no problem. I had everything grouped properly. I'm rendering a entire city here all the buildings are covered in a mirrored metal. there is street lights everywhere. I got 16 city blocks complete with street lights. Each block has got 20 street lights that work of course then there is other lights too light up the court yards. It's rendering man no problem. Group, it's the only way to get it done properly. The render will appear to stop at some points cause one building is reflecting on a different building causing a hall of mirrors effect. That will almost kill ya in Ultra setting cause it's set to 16 tries each photon or ray before it gives up. The sky will kill ya around the horizon Vue will creep around 40 to 60% complete because of this, every pass around the horizon will slow down around those areas. Volumetric skies will kill ya too if there too complex. Like to many cloud layers. Try also you may want to turn the fall off a bit more on the lights so it gives up faster on them and softness on lights could add days to a render. You got to watch settings you can't go overboard on anything. Looking at lights threw lights will kill ya. That was the problem with my street lights. I ended up moving them further appart to prevent it.