Version: 2.17.853
I should start by saying I could not duplicate this again, but am posting just incase anyone else managed it, so its probably not a bug.
This only happened on Windows 2000 (fully updated SP4 and all updates etc) with a FAT32 partition (as the drive is only 30gb anyway)
Anyway after cleaning free space, in the root directory (just C:) there were a dozen or so files with random names and extensions, about 1gb each. I did not think to save a screenshot at the time (sorry)
I tried to duplicate this (I was using real mode) , both in Real and Safe modes but could not, nor have I been able to duplicate this on XP at all.