Windows 10 rediscovered its appetite for share last month as it grew to represent almost 70% of all instances of Microsoft's OS.

According to U.S. metrics vendor Net Applications, Windows 10 grew by 1.2 percentage points to reach 60.6% of global operating system share in August, accounting for 69.6% of all Windows editions. As usual, the second number is the more important of the two; August's was 1.4 points higher than July's.

Windows 10's percentage of only Windows PCs (that's the 69.6%) was larger than the percentage of all personal computers (the 60.6%), because Windows does not power every system. In August, Windows was the OS of slightly fewer than 87% of the world's personal computers, down just half of one-tenth of a point from July. Of the remaining 13%, all but four-tenths of a percentage point ran macOS, Linux or Chrome OS.

As Windows 10's share ticked up, Windows 7's tocked down.

The aged OS, which Microsoft struck off the support list in January, lost a little bit more than a percentage point of share of all PCs, dropping to 22.3%. That translated into 25.7% of Windows PCs only, a decline of 1.1 points from July.

In the seven full months since Windows 7's retirement from support, the operating system has lost 3.3 percentage points, representing a downturn of approximately 14%.

While that may seem a notable decline, it was nowhere near the pace Computerworld projected (at the end of January) the OS would take through the remainder of 2020. Then, the trend of the previous 12 months pointed to a decline of around a point per month, putting Windows 7 under the 20%-of-all-Windows-PCs bar by September, then falling even further – to around 17% – by year's end.

As it turned out, that forecast was much too optimistic – even though it was in line with how Windows XP had behaved in 2014 – because it didn't account for the of Windows 7-to-Windows 10 migrations after the former's support deadline came and went. Microsoft's Extended Security Updates (ESU) for Windows 7, a pay-for-post-retirement-support program, may have had an impact here.

Instead of sliding under 20% by September, Windows 7 now looks unlikely to hit that mark until April 2021. And 17%? Figure the second half of July or first half of August for that. (Remember, these numbers are for percentage of Windows, not all personal computer operating systems.)

Computerworld's forecast for Windows 10 taps those same months, but matches them with different figures. By April, Windows 10 may be close to 75%. Come July 2021, Windows 10 should account for an astounding 80% of Windows editions. (Looking a long way ahead, Windows 10 may hit 90%...in May 2023.)

Elsewhere in Net Applications' numbers, August saw the first significant retrenchment by Linux since an uncharacteristic growth spurt started in April. The category, which lumps together all distributions, lost nine-tenths of a percentage point, falling to 2.7%. macOS recouped six-tenths of a point last month, pushing to near 9.6% and almost reaching its April mark.

Net Applications calculates operating system share by detecting the agent strings of the browsers used to reach the websites of Net Applications' clients. The firm tallies visitor sessions of those browsers to measure global operating system activity.