XP System Restore
The XP System Restore wants to watch external harddrives too even this is completely useless and only great for screwing up system restore points by not having the same disks attached when required.
Manually disabling System Restore for a drive is lost when a restore point is created while the drive isn't attached. In practice it must be disabled again and again for USB hard drives.
Since Vista only the system drive is watched.
USBDLM can try to disable the system restore for USB and Firewire drives but this is experimental. In most cases it works but sometimes it does not.
[Settings]
DisableSystemRestoreForNewDrives=1
Furthermore USBDLM can try to delete the beloved "System Volume Information" folder:
[Settings]
DeleteSviFolder=1
Caution: If the drive contains data of a system restore point of a foreign XP computer then these data are lost of course and this system restore point is screwed up. But this it the case too if the drive is just not there...
If the delete attempt fails then USBDLM can stop the System Restore Service for a moment and try again:
[Settings]
DeleteSviFolder=2
To prevent at least the system restore scans around the disk and fills the "System Volume Information" folder, USBDLM can add a value to the registry which prevents files and folders being backed up by NT-Backup and the system restore.
http://www.tweakxp.com/article37472.aspx
[Settings]
AddNewDrivesToFilesNotToBackup=1