Microsoft's lofty goal to hit one billion Windows 10 installations just three years after its debut was apparently a bit too optimistic.

When probed on the matter by ZDNet's Mary Jo Foley, a spokesperson for the Redmond-based company noted that they are pleased with their progress but due to "the focusing of" its phone hardware business, it will take longer than originally anticipated to reach the one billion monthly active devices goal.

If you recall, Microsoft's Terry Myerson set the mark at Build 2015 just ahead of Windows 10's summer launch. The one billion installation figure was to include all devices running Windows 10 including desktop PCs, tablets, notebooks, Windows Phones, Xbox One consoles, HoloLens headsets, Surface Hub conferencing systems and IoT devices.

Windows 10 got off to a hot start as it found its way to more than 300 million devices by May of this year so what caused Microsoft to dismiss the goal, you ask?

Back in March, Myerson conceded that Windows 10 Mobile would no longer be a focus for Microsoft over the coming years. This is the primary reason why Microsoft won't hit its 1B goal; having to rework its overreaching Windows 10 upgrade prompt tactics has only steered it further off course.

In related news, Microsoft's free Windows 10 upgrade offer ends July 29. If you haven't yet upgraded to Windows 10 and are planning to do so free of charge, your time is ticking.