How to manually uninstall Microsoft Security Essentials

This article describes how to uninstall Microsoft Security Essentials if you cannot uninstall it in Control Panel by using the Add or Remove Programs item or the Programs and Features item in Windows Vista and Windows 7. We recommend that you verify that you cannot uninstall by using Add or Remove Programs first.

Note Use this Knowledge Base article only if you are running Microsoft Security Essentials version 1.0.1963 or an earlier version (1.0.1407.0, 1.0.1500.0, 1.0.1610.0, 1.0.1961.0). If you're running a version of Microsoft Security Essentials that begin with the number 2, visit:

2483120 How to manually uninstall Microsoft Security Essentials 2.0.1963 if you cannot uninstall it by using the Add or Remove Programs item

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RESOLUTION

Note Antivirus software is designed to help protect your computer from viruses. You must not download or open files from sources that you do not trust, visit websites that you do not trust, or open email attachments when your antivirus software is disabled. For more information about computer viruses, click the following article number to view the article in the Microsoft Knowledge Base:  

129972 Computer viruses: description, prevention, and recovery

This article describes how to uninstall Microsoft Security Essentials if you cannot uninstall it in Control Panel by using the Add or Remove Programs item or the Programs and Features item in Windows Vista and Windows 7. We recommend that you verify that you cannot uninstall by using Add or Remove Programs first.

You may find it easier to follow the steps if you print this article first.

First, verify that you cannot uninstall Microsoft Security Essentials by using Add or Remove Programs in Windows XP or the Programs and Features item in Windows Vista and Windows 7. To do this, follow these steps:

Windows XP

1. Click Start, click Run, type appwiz.cpl in the Run text box, and then click OK.
2. Select Microsoft Security Essentials, and then click Uninstall.
3. Restart the computer, and then go to the "Step 3: Reinstall Microsoft Security Essentials" section.

Windows Vista or Windows 7

1. Click
   
   , and in the Search programs and files text box, type Appwiz.cpl, and then press ENTER.
2. Right-click Microsoft Security Essentials, and then click Uninstall.
3. Restart the computer, and the go to the "Step 3: Reinstall Microsoft Security Essentials" section.

If you were able to uninstall Microsoft Security Essentials by using the previous steps, you are finished. If you were unable to uninstall Microsoft Security Essentials, you may have issues with the Add or Remove Programs dialog box, and some Microsoft Security Essentials components may not be uninstalled. In these cases, you may be unable to reinstall Microsoft Security Essentials.

To have us uninstall Microsoft Security Essentials by using an alternative method for you, go to the "Fix it for me" section. To uninstall Microsoft Security Essentials by using an alternative method yourself, go to the "Let me fix it myself" section.

Fix it for me

To fix this problem automatically, click the Fix this problem link. Then click Run in the File Download dialog box, and follow the steps in this wizard.

Fix this problem
Microsoft Fix it 50535

Note This wizard may be in English only. However, the automatic fix also works for other language versions of Windows.

Note If you are not on the computer that has the problem, you can save the automatic fix to a flash drive or to a CD so that you can run it on the computer that has the problem.

Let me fix it myself

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Note You must be logged on to Windows by using a user account that is a computer administrator to complete this method. If this is your personal computer, you are likely already logged on by using an administrator account. If this is a computer that is part of a network, you might have to ask the system administrator for help. To verify that you are logged on to Windows by using a user account that is a computer administrator, visit the following Microsoft website:

http://support.microsoft.com/gp/admin

To uninstall Microsoft Security Essentials if you cannot uninstall it by using the Add or Remove Programs or the Programs and Features item, follow these steps.

Step 1: Back up the registry

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756 How to back up and restore the registry in Windows XP

Back up the registry (Windows Vista)

Back up the registry (Windows 7)

To back up the registry, follow these steps, as appropriate for the operating system that you are running.

Windows XP

1. Click Start, click Run, type regedit in the text box, then press ENTER.
2. In the navigation pane (the left pane) of Registry Editor, right-click Computer, and then click Export.

Windows Vista or Windows 7

1. Click
   
   , then type regedit in the Search programs and files text box.
2. Click Regedit.
3. In the navigation pane (the left pane) of Registry Editor, right-click Computer, and then click Export.

Step 2: Delete registry subkeys for Microsoft Security Essentials

Stop the Microsoft Security Essentials Process:

1. Open Task Manager. To do this, follow these steps, as appropriate for the operating system that you are running:
   1. For Windows XP
      • Click Start, click Run, type taskmgr, and then click OK.
   2. For Windows 7 and for Windows Vista
      1. Click
         
         , and then type taskmgr in the Search Programs and Files text box.
      2. Click taskmgr.
2. Click the Process tab.
3. Find the msseces.exe file entry. Right-click the entry, and then click End Process. If a confirmation window appears, click End Process.

Stop and disable the Microsoft Security Essentials service:

1. On Windows XP, click Start , or on Windows Vista or on Windows 7, click
   
   , and then click Run.
2. Type net stop msmpsvc, and then press ENTER.
3. On Windows XP, click Start , or on Windows Vista or on Windows 7, click
   
   , and then click Run.
4. Type sc config msmpsvc start= disabled, then press ENTER.

Delete the Microsoft Security Essentials run key:

1. On Windows XP, click Start , or on Windows Vista or on Windows 7, click
   
   , and then click Run.
2. Type regedit, and then click OK. If a User Account Control window appears, click OK.
3. Locate the following subkey:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
4. In the details pane (right pane) click Microsoft Security Essentials , and then click Delete.

Delete the remaining MSE registry subkeys:

1. On Windows XP, click Start , or on Windows Vista or on Windows 7, click
   
   , and then click Run.
2. Type regedit, and then click OK. If a User Account Control window appears, click OK.
3. Locate the following subkey:
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Current version\Uninstall\Microsoft Security Essentials
4. In the details pane (right pane), click Microsoft Security Essentials, and then click Delete.
5. Under the alphanumeric keys, search for the following entries, right-click each entry, and then click Delete for each instance that you find:
   • Microsoft Antimalware Service XX-XX Language Pack (Be aware that the XX-XX placeholder is actually the installed locale id, such as DE-DE for the German MSE. Therefore, this key is not present on en-us installations)
   • Microsoft Antimalware
   • Microsoft Security Essentials
6. Locate the following subkey:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Security Essentials
7. In the details pane (right pane), right-click Microsoft Security Essentials, and then click Delete.
8. Locate the following subkey:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Antimalware
9. In the details pane (right pane), click Microsoft Antimalware, and then click Delete.

Delete installer subkeys:

1. On Windows XP, click Start , or on Windows Vista or on Windows 7, click
   
   , and then click Run.
2. Type regedit, and then click OK. If a User Account Control window appears, click OK.
3. Locate the following subkey:
   HKEY_CLASSES_ROOT\Installer\Products
4. Under the alphanumeric keys in the ProductName field, search for the following entries. Note the numbers for each instance that you find. Then, right-click each entry, and click Delete for each instance that you find:
   • Microsoft Security Essentials
   • Microsoft Antimalware
   • Microsoft Antimalware Service XX-XX Language Pack (Be aware that the XX-XX placeholder is actually the installed locale id, such as DE-DE for the German MSE. Therefore, this key is not present on en-us installations)

Step 3: Reinstall Microsoft Security Essentials

1. Visit the following Microsoft website: http://windows.microsoft.com/en-US/windows/products/security-essentials
2. Click Free* Download.
3. Click Run, and then follow the on-screen prompts until the installation is complete.
4. Restart the computer.