I was toying around with a Pre-installment Environment program and, upon rebooting, I got an error message saying that a NTFS file consistency check was needed and had found a few errors that it corrected. I rebooted and used Goback to revert to a safe state several hours before I started fooling around. After the required reboot though I got another NTFS consistency message. This time I aborted the consistency check before any changes were made, but noticed a significant slowdown in the system and had to abort some programs manually in order to reboot again. This time I allowed the consistency check to proceed and run its course. Everything seems normal now, but I was shaken somewhat by that consistency check after running Goback. I thought Goback would have reverted everything to a previous safe state.