My office has this weird problem since upgrading to 2016.  Sometimes when in an assembly, doesn't matter the size, if we open a part in that assembly, and then close the part, even without editing it, it takes FOREVER to close that part.  Usually about 30 seconds plus,  this happens even if we open up a part that's not even in the assembly.  But if we open up any parts without the problem assembly open, it closes down just fine. It's almost like it is rebuilding every time but usually rebuild times are not so long.

Here are some details

Are computers are fast, looking at performance when this happens are CPU isn't hardly touch, our ram isn't even halfway used and we all have Solid State Drives.

We do have PDM professional but it doesn't matter if the assembly/parts are checked out or not

We are on gigabit Ethernet

All our parts are saved and rebuilt to the Solidworks 2016.

I  rebuilt the database index for good measure

This happens even if we reboot our computers and solidworks is the only thing open

The problem is sporadic. Sometimes the assembly we have issues on will function with no problems