This looks like a duplicate of TangentLaser’s 2nd problem in this thread:
This annoying problem is rare and difficult to reproduce. It is not related to V-Ray or Maxwell, although the presence or absence of any plug-in, or a reinstall might influence whether or not the bug shows up. It is actually caused by a bug in very old core Windows code which we have to carefully work around. I believe I have fixed this in SR11; at least I can no longer reproduce it. Please let me know if you are still seeing the bug in SR11.