I have found after my last save, the Datum Planes of the assembly have just lengthened in two directions monstrously for no reason. I checked to see if it was an unassebled straggler but cant find anything. Is there a way of knowing why it does this.
Check attached image, the dot is a machine 20 metres high and the datum plane seems to reach the nearest neighbourhood for some reason.
if the datums on the parts are set to auto resize, then it could be in the part sketch, maybe some projected geometry, try opening each one seperatly.
Autodesk Product Design Suit 2012
Win 7 Enterprise 64bit
Intel core i7 2600K Clocked @ 4.7GHz
Nvidia GTX 580
.... They were set to Automatic update. I found the problem though, I took the constraints off a suspect part and it was a tangent constraint throwing out the planes. All great now.
You live and learn!!