Update: OS X Yosemite powers more than half of all Macs

Apple’s OS X Yosemite powered more than half of all Macs last month, according to data recently released by analytics vendor Net Applications.

Yosemite accounted for 51.4% of all instances of OS X in February, up from 48.5% the month before. The analytics company estimates operating system user share by counting visits to the websites that deploy its metrics software.

Apple released Yosemite four and a half months ago.

By comparison, OS X Mavericks, Yosemite’s predecessor, ended its fourth month with a user share of 45%, while 2012’s Mountain Lion — the last edition with a price tag — had a 32% share at the same post-launch point. Mavericks took 6 months to equal Yosemite’s four-month mark of 51%, while Mountain Lion never made it to a majority: It topped out at 48% the month before Mavericks’ debut.

It will be interesting to see where Yosemite peaks: Can a free upgrade policy push an OS edition into territory usually only seen by, say, iOS?

Mavericks crested at 64% in its 10th month after release, powering almost two-thirds of all Macs. Can Yosemite, which has a two-month uptake lead over Mavericks, drive adoption to 80%, Computerworld‘s current estimate for Yosemite’s September 2015 share?

Seems unlikely. Apple will almost certainly preview OS X 10.11 — another California-themed operating system — which will again draw the earliest adopters to drop its forerunner. More importantly, for all the rush to Yosemite in its early months, OS X suffers from a certain degree of fragmentation, with small fractions of the Mac user base continuing to stick with older editions. Even in a best-case scenario, Mavericks, for instance, will probably still have around 10% by the time Yosemite’s heir launches.

But Apple’s 2013 bet to make OS X upgrades free has done what Apple said motivated its decision: Move more Mac users to new editions. “What’s most important to us is seeing the software in the hands of as many Mac users as possible,” said Craig Federighi, Apple’s chief of software engineering, during the October 2013 event where he announced that OS X Mavericks would be free.

At the same presentation, Federighi made another promise. “Today, spending hundreds of dollars to get the most out of your computer are gone,” Federighi said while a slide behind him showed the packaging for Microsoft’s Windows 8 Pro, with its $199 retail price prominent.

Federighi was more prescient than he probably expected: 14 months later Microsoft announced that it would give away Windows 10 upgrades to consumers running Windows 7- and Windows 8.1-powered PCs later this year. That free upgrade offer will run for one year after Windows 10’s official launch.

More importantly, Microsoft has also pledged to provide free updates and upgrades to Windows 10 for an as-yet-not-specified period that will hinge on how the Redmond, Wash. firm defines the “supported lifetime” of a device.