When Internet Explorer “Compatibility Mode” Bites: Escaping the Intranet Zone

We’ve had a number of clients recently hit by severe rendering issues when viewing their website in Internet Explorer (up to and including version 11). This normally only occurs within the company network, and not externally.

We’ve discovered that this can be caused by IE switching into “Compatibility Mode”. This mode is meant only for supporting old websites that were designed to work with IE 7 and earlier (pre-2009) — and it should not be enabled for modern websites.

Sometimes (rarely) this becomes enabled because a user has accidentally hit the button on their toolbar.

This button enables “Compatibility Mode” for the current domain

Normally on our sites we apply a <meta> tag or HTTP header which hides this button and prevents a user selecting it.

<meta http-equiv="X-UA-Compatible" content="IE=edge" />
and/or
X-UA-Compatible: IE=edge

However, in some cases these overrides do not work because there’s another setting that takes even greater priority. It’s when both of the following are true:

• The website domain is placed within IE’s “Intranet Zone”
• IE Settings Menu > Compatibility Mode Settings >
  “Display intranet sites in Compatibility Mode” is checked

Unfortunately when both of these options are set (usually by a network administrator via Group Policy), we cannot override this.

Testing

You can quickly check if this is your problem by disabling the following settings on your own machine:

After changing the setting, refresh the page and check if the layout problems have resolved.

Changing the settings above are not a proper fix, however, because it may affect your ability to use other intranet applications.

The Solution

The website needs to be removed from being in the “Intranet Zone”.

Most of the websites and intranets developed by Yump do not require ADFS, Windows single-sign-on, Internet Explorer intranet zone, nor compatibility mode. It’s quite possible that some of your corporate applications do require being in the Intranet Zone but since these are applied on a per domain basis, the main website can be safely removed without affecting the others.

This is how to remove the site from the Intranet Zone via Group Policy:

Ensure you remove the affected site from this list, while keeping any other legacy applications.

Unfortunately these settings won’t take affect immediately. Group Policy is normally applied:

1. When the computer starts
2. When the user logs on
3. Optionally reapplied on a periodic basis. By default, every 90 minutes, but these settings may differ on your network.

But in time it should filter through to your entire network.

Please contact support (at) yump.com.au if you require further assistance or have feedback.