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Troubleshooting Windows Defender
Article ID: 555957 - View products that this article applies to.
This article provides the troubleshooting information on Windows Defender application,
Windows Defender is a new security program that helps to protect your PC from spyware and other unwanted software. This program works on Windows XP & Vista. You may encounter various issues with the Microsoft Windows Defender application. This article explains you the various issues with the troubleshooting procedures.
Unable to Start Windows Defender program in Windows XP:
At the startup of Windows XP, you may see an error that says "Unable to Start Windows Defender service". This issue occurs, if some of the registry entries are corrupted. Restarting the service from the service console may also prompt the same error.
To resolve this issue, you may need to uninstall and reinstall the Windows Defender. Follow the below mentioned steps:
1. Click Start, Control Panel.
2. Click Add or Remove Programs.
3. Click Windows Defender, and click Remove.
This will uninstall Windows Defender. You can download and reinstall the updated version from the following link:
Unable to Uninstall Windows Defender in XP:
This issue happens due to corrupted DLL library. To resolve this error, download and run the Microsoft Installer Cleanup Utility. Download it from the following link:
You can also try uninstalling the Windows Defender program by running the uninstall command option from Run.
Click Start, Type Run, and type the following:
msiexec /uninstall windowsdefender.msi /quiet /log uninstall.log
NOTE: This method only works in Windows XP and is not applicable for Windows Vista.
Troubleshooting Code Errors with Windows Defender program:
While updating the definitions of Windows Defender automatically, you may experience different code errors. This is due to some setting in Windows update. Follow the steps mentioned below to resolve the same:
1. Click Start, All Programs, Windows Update.
If the update engine is taking you to Microsoft Update, you should change it to Windows Update.
2. Click Change Settings option in the left pane
3. Uncheck "Use Microsoft Update".
This should resolve the issue. If the problem persists, perform the steps mentioned in the following KB articles:
Also, you can manually download and install the Windows Defender definitions. Visit the following link and download 32-bit or 64-bit based on the version of your Windows Operating system:
Incase of any problems with downloading the definition, or running the program due to severe virus/malware attach, perform a PC safety scan. Visit:
This will remove any Virus, Malware, or spyware from the system and allows you to continue with your task.
Windows Defender says "Service has stopped" when the application is launched:
If you are using a third party spyware/malware program, it may disable the Windows Defender service. To start the Windows Defender service again, perform the following:
1. Click Start, Type Run. (You can also use Win Key + R)
2. Type services.msc
3. Right-click Windows Defender service and Click Start.
To Stop the Windows Defender application, you can follow the same steps, and Stop it.
However, if you don't want to use the program at all, change the Startup type to "Manual" from the Services Properties. Right-click Windows Defender, and click Properties to see the option.
Windows Defender is taking long time to perform a full scan:
This issue happens due to temporary Internet files, cookies, and other applog files. To resolve this issue, it is recommended to remove all these files before you schedule a full scan.
Also, update the definition pack before you perform a full scan to remove the latest spyware.
Reporting Spyware information to Microsoft:
You can report the identity of any spyware to Microsoft. Check the following link for more information:
Article ID: 555957 - Last Review: August 11, 2007 - Revision: 1.0
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