Windows 10 adoption started out very strong, but slowed quickly as the months progressed. Microsoft was aiming for 1 billion devices running Windows 10 in two to three years but backpedaled on that goal.
The operating system was installed on over 75 million PCs in its first four weeks and passed 110 million devices after 10 weeks, 200 million in under six months, 270 million after eight months, 300 million after nine months, 350 million after 11 months, 400 million after 14 months, 500 million after 21 months, and 600 million after 27 months. In September, after 37 months, it passed 700 million devices.
Windows 10 had 38.14 percent market share in November and gained 1.08 percentage points in December to hit 39.22 percent. Windows 10 market share growth has been slowed ever since the free upgrade expired in July 2016.
Windows 8 slipped 0.05 percentage points to 0.88 percent, while Windows 8.1 lost 0.14 points to 4.45 percent. Together, they owned 5.33 percent of the market at the end of December. The duo’s peak was 16.45 percent back in May 2015.
Windows 7 dropped 1.99 percentage points, falling from 38.89 percent to 36.90 percent. This is what made it possible for Windows 10 to become the “most popular desktop OS” in December. Windows 7 overtook Windows XP way back in September 2012, and passed the 60 percent market-share mark in June 2015.
Windows Vista doesn’t even register anymore (it fell below 1 percent market share at the start of 2017, the month of its 10-year anniversary). Windows XP somehow rebounded 0.31 points to 4.54 percent.
Market share breakdown
Windows overall slipped 0.83 percentage points to 86.20 percent in December. Year-over-year, Windows lost share, from 88.51 percent in December 2017.
Between November and December, macOS gained 0.94 points to 10.65 percent while Linux gained 0.70 points to 2.78 percent. Year-over-year, macOS was up from 9.02 percent share and Linux was up from 2.12 percent share.
Net Applications uses data captured from 160 million unique visitors each month by monitoring some 40,000 websites for its clients. This means it measures user market share.