What you do in System Restore is revert to a saved restore point.
If no restore point exists on your computer, System Restore has nothing to revert to so the tool won't work for you. If you're trying to recover from a major problem, you'll need to move on to another troubleshooting step.
The amount of space that restore points can take up is limited (see Restore Point Storage below) so old restore points are removed to make room for newer ones as this space is filled up. This allotted space can shrink even more as your overall free space shrinks, which is one of several reasons why I recommend keeping 20% of your hard drive space free at all times.
Important: Using System Restore will not restore documents, music, emails, or personal files of any kind. Depending on your perspective, this is both a positive and negative feature. The good news is that choosing a restore point two weeks old won't erase the music you bought or any emails you've downloaded. The bad news is that it won't restore that accidentally deleted file you wish you could get back, though a free file recovery program might solve that problem.
More About Restore Points
My description above is a good overview of restore points and how they work with System Restore but depending on the problem you're trying to address, some of the more advanced restore point information below might be helpful:
Restore Point Creation
A restore point is created automatically before:
- a program is installed, assuming the program's installer tool is compliant with System Restore.
- an update is installed via Windows Update.
- an update to a driver.
- executing a System Restore, which allows for undoing the restore.
Restore points are also created automatically after a predetermined time, which differs depending on the version of Windows you have installed:
- Windows 7: Every 7 days if no other restore points exist over that time frame.
- Windows Vista: Every day if a restore point was not already created that day.
- Windows XP: Every 24 hours no matter what restore points already exist.
You can also manually create a restore point at any time. See How To Create a Restore Point for instructions.
What's In a Restore Point
All necessary information to return the computer to the current state is included in a restore point. In most versions of Windows, this includes all important system files, the Windows Registry, program executables and supporting files, and much more.
In Windows 7 and Windows Vista, a restore point is actually a volume shadow copy, a kind of snapshot of your entire drive, including all of your personal files. However, during a System Restore, only non-personal files are restored.
In Windows XP, a restore point is a collection of important files only, all of which are restored during the System Restore. The Windows Registry and several other important parts of Windows are saved, as well as files with certain file extensions in certain folders, as specified in the filelist.xml file located in C:\Windows\System32\Restore\.
Restore Point Storage
Restore points can only occupy so much space on a hard drive, the details of which vary greatly between versions of Windows:
- Windows 7: On drives of 64 GB or less, restore points can take up to 3% of disk space. On drives over 64 GB, restore points can take up 5% or 10 GB of space, whichever is less.
- Windows Vista: Restore points can occupy up to the less of 30% of the free space on the drive or 15% of the total space on the drive.
- Windows XP: On drives of 4 GB or less, only 400 MB of space can be reserved for restore points. On drives over 4 GB, up to 12% of the disk space can be had by restore points.
It is possible to change these default restore point storage limits.