The other day I made a zip file of a large local SVN repository and copied, albeit mistakenly, to my Windows Desktop. Basically, I let the mouse go too soon and the file landed on my Desktop rather than the root of my C: drive. I didn’t really think too much of it at the time and decided it would be fine sitting there since it was to be a short lived thing. Over the next few days I had noticed the fans on my machine cycling up and down and a quick glance at Process Explorer revealed that it was explorer.exe was eating up one CPU.
Having read the title you already know the problem. Basically, I fired up Filemon to find explorer.exe chewing away on that zip file. I’m not exactly sure what it was doing but I deleted the file and explorer settled back down. The zip had been on my desktop for several days and the machine is on 24/7 (it also runs a VPC for a SVN build status machine) so I’m not quite sure why explorer never finished whatever it was trying to do but anyway, problem solved.