I have a few open cases of this in product support at the moment. WebDev.Webserver is throwing this message out and not our product but nonetheless it is worth us looking into.
The basic assumption I have is it's something to do with a removable disk as "DR2" is conventionally Windows device name for a removable disk.
I'd check all your USB disk drives are plugged in and see if that works. I also suspect that file hosting solutions that install a drive mapping may also be to blame. If you don't need the drivers for any of these I would try uninstalling the software.
Finally, there seem to be a few mentions that USB drives mapped as C:\\ will cause this to happen. Try assigning a different letter
to the drive.