The conditions for this crash are kind of specific so I'll try to be as through as possible.
I have an unwrapped mesh with 3 UVW channels collapsed down to an Editable Poly. I stick a UVWunwrap modifier on it, go to edit the UVWs, then collapse it back down to an Editable Poly. I click Hold/yes on the dialogue box.....and the viewport crashes.
If I just click yes, it doesn't happen. If I don't edit the UVWs (that is, if I just add the modifier and collapse it without hitting edit), it doesn't happen. I can still select objects in the scene, and access all the editing tools, but the viewport stays frozen. Redraw all viewports does nothing. Opening a new file clears out the frozen viewport, but then it just stays empty. I have sequential saves of the file and this doesn't happen for saves 01 - 11, but 12 - 14 all have the same problem. The only changes I made between 11 and 12 was deleting all the lighting in the scene.
Has anyone had this problem? Did I break my UVWs somewhere along the way? Is there a fix, or is this just a corrupted file?

Don't you love software?

Have you tried exporting an obj and reimporting into a new scene?

I figured it out. It was only happening on objects with the XoliulShader on it. So I'm gonna hop over there and let him know.