OK here's an odd one that happened tonight.
I was working away building assemblies when one new assembly started to lose all the new parts added to it. The parts were in the file, but the feature manager showed empty. All the existing assembly files show the parts OK, just the newly created ones. I closed the file and reopened. No change. I restarted SolidWorks - no change. I restarted the machine - everything works fine!
This is on Windows 7 32 bit.
It sounds like somehow the assembly changed to Lightweight. Right clicking on the assembly will give you an option to set to resolved or set to lightweight based on the current state.
Or it could be something completely different...
Thanks Chris but no it is not that. The parts are all fully resolved. It is almost as though the feature tree does not wake up until it is forced to open/close parts. Works fine in XP, this is just happening in Windows 7.
This is from left field but, are your video drivers up to date for Win7? I always hate the standard "it's your video card" response, but it never hurts to make sure either.
Chris
Update: I think I have sorted this. The key seems to be to right click on a component in the modelling window, and edit the component, then open it, save it, rebuild the assembly and the feature tree items appear.