The Google Analytics Mystery of the "Unset" OS

Posted by Jason Stewart on April 4, 2012

Operating System Not Set - Pie Chart

Following up on a routine check to see how much of our traffic is coming from mobile devices and tablets yesterday, I noticed something really strange in Google Analytics. Google couldn't identify the operating system of 45% of my visitors, and tagged them as "not set."

In and of itself, that is pretty strange. OS is something Google Analytics usually just knows. But the mystery deepens...almost 100% of those "not set" visits occurred during a traffic spike we were experiencing during a live event we were sponsors at ... the Adobe Digital Marketing Summit in Salt Lake City, UT.

Thoughts? Ideas? This is typically something that GA handles no sweat, so it is puzzling to say the least.

Side note, the mobile traffic is still pretty low, extremely small percentage of overall traffic. Is there some sort of guideline to consider, or a benchmark for when you need to seriously consider a mobile version of a B2B website? In our case, home page and website content is already built using HTML5 so it is typically fine for mobile devices. What do you think?