With Windows 10 imminent, Windows 8.1 sales demise clock to start tickin'

The impending debut of Windows 10 will start the clock ticking toward a deadline in 2016 when Microsoft will stop selling Windows 8.1.

The impending debut of Windows 10 near the end of next month will start the clock ticking toward a deadline in 2016 when Microsoft will stop selling Windows 8.1 at retail, and a 2017 shut-off of sales of new devices armed with the soon-to-be-forgotten OS.

According to a long-established policy called "end of sales," Microsoft stops shipping an operating system to retailers one year after the launch of the OS's successor, and mandates that OEMs (original equipment manufacturers) stop pre-installing the older edition two years after the successor's release.

Those deadlines would signal an end to retail sales in 2016 -- likely in October, a month Microsoft favors for the stoppages -- and a close to new Windows 8.1 devices in 2017.

Microsoft's policy is more a guideline than anything: Retailers typically continue to sell a blocked edition of Windows from their stockpiles for years. And Microsoft itself has bent the rules. It has not yet called an end to OEMs selling Windows 7 Professional -- the business-grade SKU (stock-selling unit) -- even though by past practice that should have been halted in October 2014.

Instead, Microsoft went through a dance of first posting an Oct. 30, 2014, end-of-sales date for Windows 7, then retracted it, then restored it but only for consumer systems equipped with Windows 7 Home Premium. At the same time, Microsoft left the date blank for the halt of Windows 7 Professional installed on new PCs, saying only it was "not yet established."

That placeholder remained today, with the additional caveat that Microsoft will give customers and OEMs a one-year heads-up before it shuts down Windows 7 Professional on new devices. In other words, Microsoft will let computer makers factory-install the OS at least through June 18, 2016.

Windows 7 remains very popular, powering 58% of all personal computers last month, and 63% of those running a Microsoft OS, according to metrics vendor Net Applications' reckoning. (The numbers are slightly different because Windows accounted for 91% of the operating systems on personal computers in May, not 100%.)

It's unlikely many will miss Windows 8.1 when it vanishes from the scene in the next two years, or much, much sooner. Today, for example, Dell jumped the push-Windows 8.1-off-the-cliff by taking pre-orders for new notebooks and desktops equipped with Windows 10, saying it would ship them July 29.

With Microsoft's free one-year Windows 10 upgrade from Windows 7 and Windows 8.1, and the aggressive marketing from OEMs, within weeks Windows 8.1 will start to dwindle in usage on existing devices and be hard to find on new hardware.

Support for Windows 8.1 will run through Jan. 10, 2023; that's not linked to the end-of-sales dates.

A more important question is when will Microsoft stop the sales of Windows 7 Professional. Business customers will be able, as always, to "downgrade" new hardware to Windows 7 via volume licensing agreements until they're ready to migrate to Windows 10 -- the latter not expected to start until the second half of 2016 at the earliest. But smaller shops that rely on Windows 7 Professional will have to arm themselves with media to do so.