In XP, this was a straightforward task, but in Vista, it requires a simple registry hack. By default, SR (System Restore) is allocated 15% of a drive’s available space. The minimum space SR needs is 300MB, which is not much space on today’s monster drives. To see how much space SR is currently using, open and elevated command prompt (Start menu>Search and type cmd and hit Ctrl+Shift+Enter and click OK in UAC) and type:
Vssadmin list shadowstorage
Now, if you want to decrease the available disk space for Restore Points, follow these directions:
- Open regedit.exe and navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore\cfg.
- In the right hand pane, double-click “Disk Percent” and change it from the default value of 15. This applies to all monitored drives.