Every so often I seem to get very high CPU usage from explorer.exe. I'll be working happily for a while, then suddenly my PC grinds to a halt. I used Procmon.exe to see what was going on, and what I can see is lots of IRP_MJ_* messages accessing files on a network share:
This is one folder with a bunch of folders and occasionally I need to copy some files out of that share to somewhere else. Some of the less used folders have been zipped up to save space, and it seems to be these zipped folders that Explorer is accessing.
This occurs even after I close all my Explorer windows - I wondered if a shell extension was causing it so I opened a few events to look at the stacks but didn't see anything out of the ordinary.
As you can see, this is all Microsoft stuff - I also used signtool to verify EXPLORERFRAME.dll and zipfldr.dll just in case. Any ideas on why Explorer might feel the need to do this would be appreciated.
My OS is Windows 2008 R2 SP1 x64.