REWORK SYSTEM RESTORE

The amount of space Windows uses for restore points is a little more complicated thana single percentage value. The Registry includes its own setting for the maximum diskspace given to System Restore, and Windows uses whichever amount is larger: thepercentage you specify via the System Properties dialog box, or the Registry'smaximum value. Any disk space you free up via System Properties won't instantly beused by System Restore; it will be available until a new restore point requires morespace than the amount allotted via the percentage value.


The percentage and maxvalues tell Windows only when to stop making new restore points.To lock in your System Restore allocation, open the Registry Editor andnavigateto HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersion\SystemRestore. Select the SystemRestore icon in the left pane to see several iconsappear in the right pane.Do not experiment with just any of these icons! While youcan safely change the value of some of them, Microsoft warns that others should notbe altered under any circumstances.


Fortunately, you can safely edit the values for theDiskPercent and DSMax icons, which control System Restore's disk-space allotments.To change the maximum amount of disk space System Restore will use (providing it'slarger than the percentage value), double-click the DSMax icon. In the Edit DWORDValue dialog box, click Decimal so you can see the specified number of megabytes inthe 'Value data' box (the default on most systems is '400'). Change this to the desiredamount, and click OK.While you're there, you can also safely edit the DSMin value, which specifies theminimum space System Restore needs to work at all.


Normally, if free space on yourWindows drive gets too low, System Restore shuts down and makes no restore pointsuntil you have at least 200MB of free space. Setting this value determines the amountof disk space at which System Restore will wake up and attempt to start saving restorepoints again.


However, just because System Restore will try to do so, it won'tnecessarily succeed if the available space is too small. Unfortunately, we know of nomethod to determine how much space a single restore point will require, so settingthis amount too low could render the feature useless.