Why does Microsoft Edge (formerly Project Spartan) prompt to open this website in Internet Explorer?

Question

Does anyone know what triggers MS Edge to not open a specific web page/site, but instead prompt the user to open the site in internet explorer?

The message says:

This website needs Internet Explorer

This website uses technology that will work best in Internet Explorer.

It is not possible to proceed using Project Spartan.

Answer 1

It is because the website is using some legacy technology. Microsoft Edge will automatically determine this and prompt the user. You'll need to figure what legacy components are there in Internet Explorer and convert those pieces to modern web standards.

Answer 2

You must send an email message to Microsoft([email protected]) and request Microsoft remove your site domain from the Compatibility View List.

https://msdn.microsoft.com/en-us/library/dd567845(v=vs.85).aspx#removal

To remove your site from the Compatibility View List (or to dispute the removal of your site from the list), have the overall site owner verify that the domain site appears in the Compatibility View List. If it does, send an e-mail to [email protected] that contains the following information:

• Owner name
• Corporate title
• Company name
• Street address
• Email address
• Telephone number
• Website address

Microsoft will review the provided information and remove your site from the Compatibility View List at the next scheduled update.

Answer 3

You can do the sitescan on http://dev.modern.ie/tools/staticscan/ to get some hints on why the site might not render correctly in MS Edge. Like Charles already said the behavoir itself is controlled by the compatiblity list. Check out this blog post for a list of older technologies that are not supported in MS Edge: http://blogs.windows.com/msedgedev/2015/05/06/a-break-from-the-past-part-2-saying-goodbye-to-activex-vbscript-attachevent/

Answer 4

There is no rule set based on the content of the page to cause this prompt.

The prompt is controlled using the "Compatibility List" which is a cloud-hosted list downloaded by the MS Edge browser periodically. It is very similar to the CV list in IE.

In most cases we are working with the sites on that list to migrate to newer technologies at which time they'll be removed from the list.