I have eraser 18.104.22.1683 on a vista machine. I am trying to erase free space on the C drive. I exited eraser from the lower left tray and started it as administrator form the start button. It started running. The log had some lines marked with error and saying the cluster tip are not erased because they are being used by another program. One was the boot. Other were marked with information (not error) and said the cluster tip were not erased because I do not have permission or they were a system file.