Event 1041 - UIPI Extension Blocked

Applies To: Windows 7, Windows Vista

User Interface Privilege Isolation (UIPI) blocks lower-integrity processes from accessing higher-integrity processes. For example, a lower-integrity process cannot send Windows® messages, or hook or attach to higher priority processes.

UIPI Extension blocking prevents the loading of some Internet Explorer® extensions that are known to be incompatible with Windows Vista® and Windows® 7, or have potential security issues. Typical extensions that could be blocked are:

  • ActiveX® Control

  • Toolbar

  • Browser Helper Object (BHO)

  • Browser Extension

  • MIME Handler

  • Pluggable Protocol

A list of known extensions are listed in the registry at HKEY_LOCAL_MACHINE (or HKEY_CURRENT_USER)\SOFTWARE\Microsoft\Internet Explorer\Extension Compatibility

When Is This Event Logged?

This event is logged when an incompatible or potentially dangerous Internet Explorer extension is encountered.


For more information and examples, see the Event 1041-UIPI Extension Blocked topic from Internet Explorer Application Compatibility.


There is no fix for this compatibility issue. You must be aware of this issue and design your Web site accordingly.

See Also


Known Internet Explorer Security Feature Issues