IE Compatibility Mode on Microsoft Edge.

[Ling_Gao]

Dear Microsoft Edge Team, Hello!

I'm currently using Windows 11 Insider Preview Build 22509. When I open the site in IE mode, I am prompted that I am using "IE (unknown)" compatibility mode at the top left of the page. I have tested with other Windows 11 computers and found that some show IE 11, some shows IE 8, and this one shows "unknown."

I would like to know why this is happening and how to modify the compatibility mode?

Thank you so much!

Best regards,
Ling Gao

[#2]

@Ling_Gao Hello!  There are a couple of ways to open a site in IE mode.  First is using group policy (What is Internet Explorer mode? | Microsoft Docs) and the second is reloading individual sites in IE mode manually (Settings and more (the ellipses icon ...) > Reload in Internet Explorer mode). 

When using policy you can select the site to load in specific document modes.

When manually selecting "Reload in Internet Explorer mode" under settings, I have seen it will say "Compatibility Mode: IE(Unknown)" but just for a short amount of time as the page is loading and then it changes to "Compatibility Mode: IE11"  Is this the scenario you are experiencing?  

-Kelly