Microsoft KB Archive/267951

= Description of the System Restore Utility in Windows Millennium Edition =

Article ID: 267951

Article Last Modified on 5/7/2007

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APPLIES TO


 * Microsoft Windows Millennium Edition

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This article was previously published under Q267951



SUMMARY
This article describes the System Restore utility in Windows Millennium Edition (Me).

The following topics are discussed in this article:
 * What is System Restore?
 * Monitored File Types
 * How to Start and Use System Restore
 * When Restore Points Are Created
 * When to Create and Use Manual Restore Points
 * The Data Store
 * Recovering from a Failed Restore Operation



MORE INFORMATION
What is System Restore?

System Restore is designed to automatically monitor and record changes made to the core Windows system files and to the registry. System Restore can then allow you to undo (or &quot;roll back&quot;) a change that caused instability in your system. This is accomplished by periodically recording a &quot;Restore Point&quot; (or System CheckPoint) that gives you the ability to roll your system back to the point in time when your computer was known to function properly.

System Restore is not intended to be an &quot;uninstaller&quot; or a backup program. If Windows does not function properly after installing software or drivers, you should use the Add/Remove Programs tool in Control Panel (or use the program's uninstaller) to remove the software before using System Restore.

Monitored File Types
System Restore monitors most system files with .exe, .vxd, .dll, .com, and .sys extensions. It does not monitor user-created files (for example, files that have .txt, .doc, or .xls extensions), the My Documents folder, Temporary Internet files (including the Internet Explorer History, Cookies, or Favorites files), the Recycle Bin, or the Windows Swap (.swp) file.

How to Start and Use System Restore
To start System Restore, follow these steps:
 * 1) Click Start, point to Programs, point to Accessories, point to System Tools, and then click System Restore.

The first time you use System Restore, there are two options on the Welcome page:


 * 1) * Restore my computer to an earlier time
 * 2) * Create a restore point
 * 3) Click Restore my computer to an earlier time and click Next.

A calendar appears.
 * 1) In the calendar, choose which Restore Point to roll your system back to.
 * 2) Click Next.

You are prompted to close all applications before completing the Restore process because the computer will restart.
 * 1) Upon completion of the restart, a confirmation screen appears. Click OK to continue using your computer.

The next time you start System Restore, you will see a third option, Undo my last restoration. This is available in the event that the Restore Point you rolled back to does not correct the original problem that you were having and so you can easily get back to the point in time that you started troubleshooting.

When Restore Points Are Created
Restore points are created under the following conditions:


 * Automatic System CheckPoints are created for every 10 hours of computer up time but only after the computer has been idle for 2 minutes. If this criterion is not met, then a System CheckPoint will be created once every 24 hours after the system has been idle for 2 minutes.
 * Restore points are created by Installer packages that use the new Microsoft Software Installer (MSI) technology.
 * Restore points are created by Installer packages that use InstallShield 6.1 Pro and later.
 * Restore points are created when AutoUpdate (AU) installs an update package.
 * Restore points are created when you use System Restore to roll your system back to a different Restore Point. However, if this is done in Safe Mode, a Restore Point will not be created.
 * Restore points are created manually by using the System Restore interface.

The Restore Point and System CheckPoint files that are created under the above conditions are stored in compressed (.cab) format and are located in the _Restore folder (also known as the &quot;Data Store&quot;) on the drive on which Windows Millennium is installed. The Data Store cannot be moved or modified. Each fixed disk on your computer will also contain a _Restore folder for indexing and monitoring purposes and each of these folders will contain a file called Srdiskid.dat.

When to Create and Use Manual Restore Points
Manual restore points can be created before installing device drivers or software if you are uncertain how they will affect the overall performance of Windows. If you are unable to use the program's uninstaller to remove the software, you can roll back to the manual restore point that you created. To create a manual Restore Point, follow these steps:
 * 1) Click Create a restore point, and then click Next.
 * 2) Enter the description of your Restore Point and then click Next to confirm the creation.
 * 3) Click OK or Home.

The Data Store

The size of the Data Store is determined by the size of the Windows drive and is as follows:


 * The minimum size of the Data Store is 200 megabytes (MB). If your Windows drive has fewer than 200 MB of free space after you install Windows Millennium, System Restore is disabled by default and you will have to manually enable System Restore after you have freed up sufficient disk space. If System Restore is disabled due to the low disk notifier, System Restore automatically re-enables itself after sufficient disk space is made available.
 * On logical drives that are less than 4 gigabytes (GB), the maximum size of the Data Store is 400 MB.
 * On logical drives that are 4 GB or larger, the Data Store is approximately 12 percent of the logical drive that Windows Millennium is installed on.

Once the Data Store reaches 90 percent of the allotted size, it begins to &quot;purge&quot; older Restore Points on a first-in first-out (FIFO) basis until the Data Store reaches 50 percent of its allotted size. The actual number of Restore Points available after this purge occurs may vary, based on what software was recently installed.

To manually adjust the size of the Data Store, follow these steps:


 * 1) In Control Panel, click System.
 * 2) Click the Performance tab.
 * 3) Click the File System button.
 * 4) On the Hard Disk tab, adjust the System Restore disk space use slider to the preferred size.

IMPORTANT NOTE: Reducing the disk space used by System Restore may FIFO existing Restore Points, so use caution when performing this action.

Recovering from a Failed Restore Operation

If your computer becomes non-bootable and System Restore was the last operation performed, you can use the Emergency Boot Disk (EBD) to revert your computer back to the state prior to the Restore operation. When you use the EBD to boot your computer, you will see the following message:

System Restore detects that a restore was the last operation completed. It is recommended you now revert the changes to your system made by System Restore and restart before you proceed. If you choose not to revert these changes, this option will no longer be available.

1)Revert the Restore changes made to my system.

2)Do not revert the Restore changes made to my system.

Enter a choice

If you select the first option, your computer reverts to the state prior to the restore operation and you are prompted to restart the computer:

System Restore reverted the chances made by the last restore operation.

Remove all disks from the floppy disk drives and press CTRL+ALT+DELETE to restart your computer.

Although it is not recommended, you can disable System Restore by following these steps:
 * 1) In Control Panel, click System.
 * 2) Click the Performance tab.
 * 3) Click the File System button.
 * 4) Click the Troubleshooting tab.
 * 5) Click the Disable System Restore check box.
 * 6) Click OK, and then click Close.
 * 7) Restart your computer when prompted.

Keywords: kbhowto kbfaq kbfile kbui KB267951

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