Meanwhile, use of Microsoft's Edge, the intended replacement for IE, continued to sink among those running Windows 10.
The latest data published Sunday by California-based Net Applications portrayed the browser battle in October as another victory for Google and its Chrome, and signaled that the looming deadline facing almost half of all IE users has not been taken seriously.
Chrome cracked the 30% bar in October, Net Applications said, with its user share -- the portion of the world's personal computer users who run a specific browser, and so a proxy for market share -- climbing by 1.3 percentage points, averaging 31.1% for the month.
That was a record for Chrome, which debuted seven years ago. In the past 12 months, Chrome has boosted its user share by 9.9 percentage points, representing a one-year growth rate of 46%.
Microsoft's IE -- all versions -- lost seven-tenths of a percentage point in October, falling to a user share of 50.9%, a record low in the Net Applications data that Computerworld has tracked over the past decade. The last time IE accounted for that amount of share was before the turn of the century, when Microsoft's browser was still chewing into the dominance of Netscape Navigator, a war that brought Microsoft into the crosshairs of U.S. antitrust officials.
Another browser that preceded Chrome -- Mozilla's Firefox -- also jettisoned users last month: Firefox lost two-tenths of a percentage point in October, dropping to 11.3%, a low not seen by the open-source developer since the summer of 2005.
If Chrome, IE and Firefox continue to gain or lose user share at the rates they have over the past 12 months, Chrome will hit 35% by March 2016, IE will slip below 50% -- a historic mark -- in December 2015, and Firefox will fall under 10%, another notable milestone, in April 2016.
Chrome's surge has been nothing but stunning, handily outpacing the growth experienced by Firefox during its strongest stretches of share gains in early 2009.
Although Chrome has historically grown at a decent clip organically, Computerworld has credited its recent user share hike to a Microsoft move that requires most IE users to update to the newest version available for their edition of Windows.
By Jan. 12, 2016, the vast bulk of IE users must run IE11 or be shut off from the browser bug-patching spigot. After that date, Microsoft will support IE9 only on the barely-used Windows Vista and Windows Server 2008, and IE10 only on Windows Server 2012. All others must run IE11 or Edge, which is available only on Windows 10.
By demanding that users switch from, say, IE 8 to IE11, Microsoft opened the door to alternatives. Because users were told they had to change browsers in any case, they have been more than half as likely to select Chrome as to update to a newer version of IE. Since the 2014 announcement, for every two users who updated to IE11 and stuck with it, 1.1 users switched to Chrome instead.
That's been disastrous for IE's share, which has plummeted 8.3 percentage points so far this year.
And while some of those who deserted IE migrated within Microsoft's ecosystem to Edge on Windows 10, the growth of Edge was not nearly enough to offset the decline of IE. Edge's user share edged up slightly in October to 2.7% of all browsers -- or 5.2% of all Microsoft browsers -- but that increase was smaller than the month prior.
Edge's share of all browsers running on Windows 10 also fell last month, according to Net Applications, with the new browser accounting for a third of those run on the new OS, a drop of nearly three percentage points from the month before.
In other words, Windows 10 users -- who have been pushed to Edge by Microsoft with tactics that included setting that browser as the default on the OS after an upgrade -- are ignoring it in increasing numbers.
Chrome also seems to have impacted the user share of Apple's Safari, a browser that in the personal computer arena runs almost exlusively on OS X-powered Macs. The percentage of all OS X users relying on Safari fell to 63%, a four-point decline from July's and August's 67%.
As of the end of October, about 47% of all IE users ran a version that will be retired from support in just 10 weeks. Expecting that number of users to switch to IE11 or Edge in such a short time is unrealistic: Computerworld now projects that between 42% and 45% of all IE users will be barred from receiving browser security updates at the Jan. 12, 2016, deadline.
The scramble to abandon older IE editions should be epic, much more dramatic than even the last-minute frenzy to get off Windows XP last year. When XP reached support retirement in April 2014, it had a user share of 29% of all versions of Windows, or about two-thirds of the low-end estimate of the percentage of IE's users who will suddenly realize in mid-January that patches have stopped.