18-25LESSON 4 USING SYSTEM RESTORELESSON 4

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Lesson 4

Using System Restore

Lesson 4: Using System Restore

System Restore is a feature that monitors changes to certain system and applicationfiles. System Restore functions like an “undo” feature for Windows XP Professionalconfiguration changes, allowing you to recover from problems caused by incorrect sys-tem settings, faulty drivers, and incompatible applications. Windows XP Professionalcreates restore points automatically, and you can also create a restore point manually.After this lesson, you will be able to

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Explain System Restore.

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Enable or disable System Restore.

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Create a restore point.

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Restore a restore point.Estimated lesson time: 30 minutes

Overview of System Restore

System Restore works by creating restore points that contain a snapshot of the Reg-istry (which includes user account, application, and hardware configuration) and acopy of certain system files that Windows XP Professional requires for startup, includ-ing those in the %systemroot% directory and boot files on the system partition. You canrestore your computer to a particular restore point at any time.By default, System Restore creates restore points when the following events occur:

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Every 24 hours if the computer is turned on or if it has been 24 hours since thecomputer was last turned on

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When you install an unsigned device driver

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When System Restore–compliant applications are installed

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When updates are installed through Automatic Updates or Windows Update

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When you restore data from backup media using Windows Backup

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When you restore a restore point

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When certain system or application files are changed

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When you create a restore point manuallySystem Restore also monitors file operations for a core set of system and applicationfiles. These files are specified in %systemroot%\System32\Restore\Filelist.xml. SystemRestore records changes to these file and sometimes copies them to a hidden archivebefore allowing the files to be overwritten, deleted, or changed.System Restore does not monitor the following files and folders:

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The virtual memory paging file

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Personal user data, such as files in My Documents, Favorites, Recycle Bin, Tempo-rary Internet Files, History, and Temp folders

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Image and graphics files, such as those with .bmp, .jpg, and .eps extensions

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Application data files with extensions not listed in systemroot\System32\Restore\Filelist.xml, such as .doc, .xls, .mdb, and .pstRestore point information is saved to a hidden folder on the volume in which a moni-tored file is located. The archive collects multiple restore points, each representingindividual system states. The files, Registry snapshots, and logs associated with olderrestore points are purged on a first in, first out (FIFO) basis, optimizing System Restoredisk space and making room for new restore points.

Real World Changing System Restore Options in the

Windows Registry

In most situations, the default System Restore operation is satisfactory. However,there might be situations in which you need to change how System Restore func-tions. There are four settings that you can change in the Windows Registry thataffect the intervals System Restore uses when creating automatic restore pointsand the disk space it uses.Each of these settings is located in the HKEY_LOCAL_MACHINE\SOFT-WARE\Microsoft\Windows NT\CurrentVersion\SystemRestore subkey. These set-tings include the following:

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RPSessionInterval This setting specifies the intervals, in seconds,between scheduled restore-point creations during an active user session. Thedefault value is 0 seconds (disabled).

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RPGlobalInterval This setting specifies the time interval, in seconds, atwhich scheduled restore points are created (regardless of whether or notthere is an active user session). The default value is 86,400 seconds (24hours).

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RPLifeInterval This setting specifies the time interval, in seconds, forwhich restore points are kept. System Restore deletes restore points olderthan the specified value. The default value is 7,776,000 seconds (90 days).

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DiskPercent This setting specifies the maximum amount of disk space oneach drive that System Restore can use. This value is specified as a percent-age of the total drive space. The default value is 12 percent.