I'm doing some work on the Displacement functions and have come across a bit of a dilemma with scene composed of thousands of WW Displacements. If you have a scene open with a large number of displacements, you may find that Max will hang (apparently frozen) when you take one of these actions: Close Max; Click File > New; Click File > Open.
Although it appears that Max is frozen, it is actually just doing something under the hood. Exactly what that is, I am not sure, but I think it's an internal event notification that is not working very efficiently, especially regarding the way WW stores data for displacements.
I cannot promise a fix directly unless it turns out that this is directly related to WW. But at the moment, I do not have reason to think this, and have recently seen some similar reports on CG Society with regarding standard Max lights, etc.
For the time being, the solution is this: Hit CTR+ALT+DEL and kill Max in Task Manager. Or wait... as Max will eventually come out of its stupor. But in the scene I'm testing, it's faster to kill Max and reopen than to wait.
Just an update.
The issue described here seems to be limited to scenes with sculpt meshes that are based off of a very large number of displacements. The number of displacements in the scene is not the issue--just having sculpt meshes with many displacements.
Also, I've discovered that the issue only manifests if you've got such a sculpt mesh and select it and open the modify panel. While this doesn't solve the problem, it can help you understand how to avoid the closing lag during sessions that don't require you to edit the sculpt mesh.
This is no longer a problem with new sculpt meshes.