Add-On

“This page wants to run the following add-on…” won’t go away in Internet Explorer

In the last few weeks, I found that a lot of users were complaining about IE11 on Windows 10, and the prompt “This page wants to run the following add-on” with the add-on name, and the allow button:

This webpage wants to run the following add-on ‘Adobe Flash Player’ from Microsoft Windows Third Party Application Compon…

However, clicking the ‘Allow’ button, or using the drop down arrow to choose ‘Allow for all sites’ did nothing, and the prompt would show again and again.

I ended up working out this was due to the Add-On List GPO to list IE add-ons that was being used to manage the add-ons I wanted disabled or enabled https://docs.microsoft.com/en-us/internet-explorer/ie11-deploy-guide/enable-and-disable-add-ons-using-administrative-templates-and-group-policy

The policy explicitly states “The ‘Deny all add-ons unless specifically allowed in the Add-on List’ policy setting will still determine whether add-ons not in this list are assumed to be denied.”

However, since a recent update (either Windows 10 1803, or a recent security patch  – unsure which!), anything not listed in the Add-On List was being blocked. 

Adding an update to the list and allowing it with the ‘1’ value fixes the issue for that particular add-in, but it shouldn’t be working this way.

I even tried disabling the Group Policy setting ‘Deny all add-ons unless specifically allowed in the Add-on List’ but that made no difference. That policy also states: ‘If you disable or do not configure this policy setting, users may use Add-on Manager to allow or deny any add-ons that are not included in the ‘Add-on List’ policy setting.’

Something wacky’s going on – if I find out more I’ll update this post, but if you do use the ‘Add-On List’ GPO for Internet Explorer, be aware of this potential issue. You may need to list all your add-ins into the policy to avoid this.

I’ve also updated all my ADMX files for Win10 1803.