Google Analytics reports a high amount of Internet Explorer 7 traffic

Our organization saw massive numbers for IE7 as well—even in 2020. This was quite puzzling until we realized a service we use to crawl our pages (Siteimprove) had a user agent that registered as IE7. The dates of the crawls lined up perfectly with the IE7 traffic.

Long story short, if you have high IE7 traffic and use any services to crawl your sites/apps, see if the crawl dates from said services line up with the traffic spikes in Google Analytics.

This has to do with the user agent reported by the browser when the site has been added in Tools->Compatibility View Settings.

Experimenting with IE11, I found that if I visit a site normally, the user agent string is:

Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko

This indicates IE11

If I open my browser's compatibility view settings, and add my domain to the list of those that should render in Compatibility View, this is my UA string:

Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/7.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)

This indicates IE7

I used this website to give me a cleaner explanation of the data in these UA strings: http://user-agent-string.info/

One interesting thing is that I can still control what mode the page renders in using the x-ua-compatible meta tag. So, if my website makes strong use of x-ua-compatible to force "edge" mode, visitors using IE11 with my domain set to compatibility view will actually render by page in IE11 mode, but will report IE7 to Google Analytics.

For our organization, the reason the IE7 number is inflated is because at one time, it was the practice of our tech support team to advise our users to add our website to their compatibility view settings to avoid issues with our legacy web apps not working in IE8.