Article ID: 240797
Article Last Modified on 8/24/2007
APPLIES TO
- Microsoft Internet Explorer 5.01 Service Pack 2
- Microsoft Internet Explorer 5.01 Service Pack 3
- Microsoft Internet Explorer 5.01 Service Pack 4
- Microsoft Internet Explorer 5.5
- Microsoft Internet Explorer 6.0
- Microsoft Internet Explorer 6.0 Service Pack 1
- Windows Internet Explorer 7 for Windows Server 2003 IA64
- Windows Internet Explorer 7 for Windows XP
- Windows Internet Explorer 7 for Windows Server 2003
This article was previously published under Q240797
Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:
256986 Description of the Microsoft Windows registry
SUMMARY
This article describes how to stop an ActiveX control from running in Microsoft Internet Explorer and in Windows Internet Explorer. You can do this by modifying the data value of the Compatibility Flags DWORD value for the Class identifier (CLSID) of the ActiveX control.
Note For Microsoft Windows XP-based and Windows Server 2003-based computers, administrators can use Software restriction policies to prevent an ActiveX control from running in any programs on computers in an Active Directory domain environment. For more information about software restriction policies, visit the following Microsoft Web site:
MORE INFORMATION
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
Warning Microsoft does not recommend unkilling (undoing the kill action on) an ActiveX control. If you do so, you may create security vulnerabilities. The kill bit is typically set for a reason that may be critical, and because of this, extreme care must be used when you unkill an ActiveX control. Also, because the following procedure is highly technical, do not continue unless you a very comfortable with the procedure and you it is a good idea to read the whole procedure before you start.
The CLSID for an ActiveX control is a GUID for that control. You can prevent an ActiveX control from running in Internet Explorer by setting the kill bit so that the control is never called by Internet Explorer when default settings are used.
The kill bit is a specific value for the Compatibility Flags DWORD value for the ActiveX control in the registry. This is different from revoking the "safe for scripting" option in an ActiveX control. When the "safe for scripting" option is revoked, Internet Explorer still calls for the control and then prompts you with a warning message that the ActiveX control may be unsafe. Depending on the choice you make, the control may be run. However, after the kill bit is set for an ActiveX control, that control is not called by Internet Explorer at all unless the Initialize and script ActiveX controls not marked as safe option is enabled in Internet Explorer. To set the kill bit, follow these steps:
- Determine the CLSID for the ActiveX control that you want to disable. If you are not sure of the CLSID for the control, contact the manufacturer. If the control is installed, you may be able to determine its CLSID if you know its friendly name. To do this, examine the Default string value for the ProgID key for each of the CLSID keys in
HKEY_CLASSES_ROOT\CLSID. You may have to remove as many ActiveX controls as possible, except for the one that you want to disable, to make it easier to identify the appropriate CLSID. For more information about how to remove ActiveX controls, click the following article number to view the article in the Microsoft Knowledge Base:154850 How to remove an ActiveX control in Windows
- Use Registry Editor to view the data value of the Compatibility Flags DWORD value of the ActiveX object CLSID in the following registry key
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\CLSID of the ActiveX controlwhere
CLSID of the ActiveX Controlis the class identifier of the appropriate ActiveX control.
Notes- Typically, you will have to manually create this registry key.
- To determine the CLSID that corresponds with the ActiveX control that you want to disable, remove all the ActiveX controls that currently are installed, install the control that you want to disable, and then add the kill bit to its CLSID.
- Change the value of the Compatibility Flags DWORD value to 0x00000400.
If a killbit is set for an ActiveX control and a new version of an ActiveX control is released with a different CLSID, you can enable Web sites that use the old CLSID to continue to work as intended. You do this by adding the new value at the same level as the Compatibility Flags value in the registry. This value should be a REG_SZ string that is named "AlternateCLSID.” The AlternateCLSID value will appear enclosed in braces. For example, it will resemble the following:
{ABCDEF12-ABCD-ABCD-ABCD-ABCDEF123456}
Internet Explorer will interpret this value and create an instance of the ActiveX control that is referenced in the AlternateCLSID value instead of the one that has received a killbit.
Note For the AlternateCLSID value to be effective, the killbit must be set on the initial CLSID.
ActiveX control developers can use the TreatAs or AlternateCLSID registry values with the "kill bit" to have Internet Explorer check to see if an updated ActiveX control has been provided for use instead of a disabled ActiveX control. For information about how to use the TreatAs value, visit the following Microsoft Web site:
To set the AlternateCLSID value, follow these steps:
- Use Registry Editor to locate the disabled ActiveX object CLSID in the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\CLSID of the ActiveX controlWhere
You can see the value of the Compatibility Flags is set to DWORD 00000400.CLSID of the ActiveX Controlis the class identifier of the appropriate ActiveX control.
- Add an AlternateCLSID string value to the CLSID key.
- Set the data of the AlternateCLSID string value to
{CLSID of the alternate ActiveX control}, where{CLSID of the ActiveX Control}is the class identifier of the updated ActiveX control.
The AlternateCLSID value instructs Internet Explorer to redirect to the CLSID for the updated ActiveX control. You can chain redirects up to ten levels deep.
The AlternateCLSID value is supported on the following versions of Internet Explorer.
- Internet Explorer 5.01 Service Pack 2 or later for Windows 2000 with MS03-004 or later
- Internet Explorer 5.5 Service Pack 2 with MS02-068 or later
- Internet Explorer 6 Service Pack 1
- Internet Explorer 6 for Windows XP with MS02-068 or later
- Internet Explorer 6 for Windows Server 2003
Note Versions of Internet Explorer that are not listed in this article are either in the extended phase of the product life cycle or are no longer supported. Although you can set the kill bit on these versions of Windows and of Internet Explorer, Microsoft recommends that you also upgrade to a supported version of Internet Explorer and apply all appropriate updates. For more information about how to determine the version of Internet Explorer, click the following article number to view the article in the Microsoft Knowledge Base:
164539 How to determine which version of Internet Explorer is installed
Keywords: kbhowto kbenv KB240797
