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I had maximum allotted system restore space for a drive set to about 4 GB But how could I gained 25 GB of free space on that same drive on turning system restore off ?


HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore

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HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore\Cfg

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Right after clearing the system restore by cycling it Off and then back On, Be sure to create a manual restore point – Moab Apr 11 '11 at 15:08
Nice utility here to manage restore… – Moab Apr 11 '11 at 15:13
How large space is the hard disk all-in-all ? – harrymc Apr 11 '11 at 15:14
@harrymc: 160 GB, On a 40 GB partition it freed up about 25 GB which was for windows directory. – cpx Apr 11 '11 at 15:25
not an ans, but you may be interested, ERUNT just backups the registry. is a good program – barlop Apr 11 '11 at 19:48
up vote 0 down vote accepted

Windows does not always automatically delete everything in the restore directory other than the 4 GB you set it to. You also could have had some malware in the restore directory. Windows will delete most stuff from the restore directory when you turn it off, so it can delete some malware files (but not always).

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The problem is that on XP, it looks like Microsoft simply ignores your setting.

From The Registry Keys and Values for the System Restore Utility for XP :


This value relates to the percentage of disk space that System Restore uses for its data store. The default value is 12 percent. The data store size is always calculated as "max(12 percent, DSMax)," regardless of the size of the hard disk.


This value specifies the maximum size for the System Restore data store. The default size of the data store is 400 MB. The data store size is always calculated as "max(12 percent, DSMax)," regardless of the size of the hard disk.

However, the 25 GB you freed on a 40 GB disk is 62,5% rather than 12%. This means that the whole algorithm is non-functional, so there are actually no real limits. One hopes that this was corrected in later versions of Windows. However, such a malfunction can easily pass unnoticed, since Windows is supposed to automatically liberate this space if required.

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