Sorry Windows 7 aficionados (myself included) who thought Microsoft's ageing operating system was getting a second wind based on the Steam Hardware Survey. Turns out the platform's resurgence was due to an "over counting" bug, which Valve has addressed as of the latest survey.
To anyone paying close attention to the survey over the last seven months would have noticed Windows 7 usage growing, rather than shrinking, which doesn't make much sense considering Windows 10 has been a thing for almost three years.
Sure, there are some edge scenarios where Windows 7 might climb a percentage point or two but, for the most part, the OS has been in steady decline for years now. Turns out it had the folks at Valve scratching their heads too. Once they investigated, the spurious numbers where attributed to a bug.
The latest edition of the survey includes a note regarding the problem, as well as the fix Valve implemented. The gist of it is that the survey is only meant to count each system once per year, however, some cyber cafes — predominately those based in China — were doing something (almost certainly unintentional) so their PCs were counted multiple times.
This gave the survey a bum steer, particularity with OS usage:
Around August 2017, we started seeing larger-than-usual movement in certain stats, notably an increase in Windows 7 usage, an increase in quad-core CPU usage, as well as changes in CPU and GPU market share. This period also saw a large increase in the use of Simplified Chinese. All of these coincided with an increase in Steam usage in cyber cafes in Asia, whose customers were being over counted in the survey.
The note goes on to say Valve is "confident" it's fixed the problem and that going forward, the survey should "no longer [be] over counting users".
Steam Hardware Survey [Steam]