When you use the Disk Defragmenter tool to defragment your hard disk, you may receive the following message:

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This issue can occur if a program (such as an antivirus program or a screen saver) is running on the drive when the Disk Defragmenter tool is running.

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To work around this issue, use one of the following methods.

NOTE: To analyze or defragment a volume you must logon using an account with administrator privileges.

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Clean Boot the Computer

A "clean" boot is a method of reducing problems that may occur because of your computer's environment. Many problems that may occur when you run Windows or other programs can occur because there are conflicting drivers, terminate-and-stay-resident programs (TSRs), or other settings that load when you start your computer. Windows XP includes a System Configuration Utility tool (Msconfig.exe) to make performing a clean boot easier.

For additional information about clean booting in Windows XP, click the article number below to view the article in the Microsoft Knowledge Base:

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Use Safe Mode

Instead of performing a clean boot, you may want to restart your computer in Safe mode, and then start the Disk Defragmenter tool. After you run Disk Defragmenter, restart your computer.

To start the computer in safe mode:

1.	Click Start, and then click Shut Down.
2.	In the Shut Down Windows dialog box, click Restart, and then click OK.
3.	Press F8 when your computer restarts.
4.	In the Windows Advanced Options menu, use the arrow keys to select the appropriate safe mode option, and then press ENTER.
5.	If you have a dual-boot or multiple-boot system, choose the installation that you need to access using the arrow keys, and then press ENTER.

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For additional information about how to troubleshoot issues with Disk Defragmenter, click the article number below to view the article in the Microsoft Knowledge Base:

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