Back in April 2015, Microsoft made the bold claim that its new operating system, Windows 10, would be running on 1 billion devices by 2018. Today, the company is revising the timeline. In a statement obtained by ZDNet, Windows marketed head Yusef Medhi says the poor performance of its mobile division means it won't likely hit its original milestone within three years after release.

"Windows 10 is off to the hottest start in history with over 350 million monthly active devices, with record customer satisfaction and engagement," he said. "We're pleased with our progress to date, but due to the focusing of our phone hardware business, it will take longer than FY18 for us to reach our goal of 1 billion monthly active devices. In the year ahead, we are excited about usage growth coming from commercial deployments and new devices - and increasing customer delight with Windows." Starting July 30th, 2016, the company will no longer give out the upgrade for free and instead will start charging $119. So the upgrade rate is expected to slow further.

"It will take longer than FY18 for us to reach our goal of 1 billion monthly active devices."

The 1 billion figure wasn't always an impossibility. Had Microsoft continued to sell around 50 million Windows Phone devices following the launch of Windows 10, it would have likely achieved its install base goal within the intended time frame, explains ZDNet. However, the writing was on the wall starting as early as January of this year, when Microsoft's quarterly earnings announcement spelled the death of Windows Phone, which saw a 57 percent year-over-year sales drop for the period. Since then, Microsoft has been careful not to completely bury its phone platform, but it's clearly said the focus is aligning elsewhere.

"We're fully committed to that 4-inch screen, there will be a time for it to be our focus, but right now it's part of the family but it's not the core of where I hope to generate developer interest over the next year," Windows chief Terry Myerson told The Verge In April. "There's no lack of recognition to realize how important that form factor is, but for Microsoft with Windows and for our platform it's the wrong place for us to lead."

A month after Myerson's comments, Gartner's smartphone sales report indicated Windows Phone had dipped below 1 percent market share for the first time. It's unlikely the mobile OS will bounce back, at least not until Microsoft dedicates more resources to it. That's not to say Microsoft's lack of mobile ambition is a huge drag on Windows 10. The OS is growing steadily, and Microsoft very well may hit its 1 billion milestone some time in the next three to four years. It just may take a little longer than the company anticipated.

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