[Osiris]

It was possible to define the percentage that the System Restore feature in Windows XP allocated from a hard drive. Windows Vista has System Restore build in as well but no obvious way to define the percentage of the hard drive that System Restore allocated. Microsoft thought it would be a good idea to hide the setting well and allocate 15% of the hard drives capacity to System Restore. On a 300 Gigabyte drive System Restore would allocate 45 Gigabytes of space !
In their drive for a uncomplicated system they restrict user possibilities to create a system the way they like. It is becoming a closed system with the owner of the computer being a user instead of someone who can actively alter his system the way he wants. To change the System Restore size in Microsoft Windows Vista you have to rely on the command line utility vssadmin.

Open the command line and use the following command to change the size of System Restore in Windows Vista:
vssadmin resize shadowstorage /on=c: /for=c: /maxsize=4GB
This would change the allocated size of System Restore on drive C: for drive C: to 4 gigabytes. Please note that the on: parameter is the drive letter where the System Restore files are stored while the for: parameter defines the drive that the files should be backed up from. The maxsize parameter is pretty obvious. It can’t go below 300 Megabytes. If you remove the maxsize parameter the settings will be changed to the default ones again.
If you select a size that is lower than the current amount of space the oldest entries in System Restory will be deleted first.