Disqus officially supports Internet Explorer version 10, though it may also work in Internet Explorer versions 8 and 9. If Disqus is loading inconsistently or not at all for you in these browsers, there are several factors that may cause this:

When Internet Explorer's Compatibility View is enabled, you may see the following message in place of the normal Disqus commenting area:

"Your browser is not currently supported in Disqus. Please use a modern browser."

This is because Internet Explorer is loading the page using an older, "compatible" version of Internet Explorer's rendering engine.

To fix this, turn off Compatibility View. See Microsoft's Compatibility View help page for steps on how to do this.

Web developers also have the option of setting their own document mode using the following:

Internet Explorer will render in Quirks Mode when the <!DOCTYPE> is either missing or doesn't comply with standards. This may result in strange Disqus loading behavior; for example, Disqus may load wider than the page, forcing a horizontal scrollbar.

To check if Internet Explorer is using Quirks Mode, open the development tools (press F12) > check the Document Mode. If it says Quirks, you can try changing this to IE8 or IE9 Standards to view the page normally.

Pages being loaded in Quirks Mode can be fixed by using a standard <!DOCTYPE>. The most common causes include:

A doctype is required to comply with rendering standards. Not including one will cause Internet Explorer to render in Quirks Mode. You can find a list of standard doctypes here.

No characters (including whitespace) can precede the doctype. Make sure it's the very first thing listed on the page.

The public identifier is the URL that comes after the doctype, and is required to comply with standards.

This doctype is incorrect because it's missing the identifier URL:

This would be the correct version with the identifier URL:

Some websites force Internet Explorer to load emulating an older version of Internet Explorer. You can check by opening the development tools (Press F12) and checking the Document Mode. If it says Internet Explorer 7 Standards, you can switch this to Internet Explorer 8/9 Standards to load Disqus properly.

The most common reason the page would load in IE7 standards is because of the EmulateIE7 meta tags. Look in your page source and find an HTML tag similar to this:

You can either remove this or change it to use the latest version of IE available:

For instructions using Blogger, see: Updating a Blogger template to support all versions of Internet Explorer