May 7, 2013 · 3 minutes

It's hard to argue that Windows is doing well. Samsung, Acer, and Nvidia have each expressed disinterest and disappointment in Windows RT, the ARM-specific version of the operating system. The IDC has held Windows 8 responsible for the 13.9 percent drop in PC shipments between the first quarter of 2013 and the year-ago quarter. Windows 8-powered tablets haven't fared much better, with the IDC estimating that just 1.8 million units shipped in the first quarter -- with 900,000 of those shipments attributed to Microsoft and its Surface tablets.

Yet Microsoft announced yesterday that it has sold over 100 million Windows 8 licenses. That's more than double the estimated 49.2 million tablets shipped in the first quarter, and on par with Windows 7, which Microsoft claims is the fastest-selling operating system ever introduced. Windows 8 is one of the least-popular operating systems of the moment; it is also matching the fastest-growing operating system in history. If ever there were a bit of software with an identity crisis, Windows 8 would be it.

Which is why it's so hard to define, quantify, and, for many, understand the operating system. I tried to explain Windows RT in March and ended up with this mess:

So, in short: Windows RT is a new operating system, built on an old operating system, that is like this other new operating system. It doesn’t act like other Windows PCs, except for when you’re using Office, but that’s the only time it acts like that, so you’ll still be using the other interface most of the time. Except when you’re not.
Windows 8 proper isn't much easier to explain, except that it allows users to interact with the traditional desktop environment and (try to) forget that the interface-formerly-known-as-Metro is even on their device. Unlike any other version of Windows, which all sport a relatively identical interface -- perhaps with a bit of grayscale here and a dollop of Aero there -- Windows 8 is radically different from its predecessors, and that lack of familiarity probably isn't doing Microsoft or the PC industry any favors.

But, hey, don't take my word for it. Here's the IDC's Bob O’Donnell in what PandoDaily contributor Kevin Kelleher described as "a suckerpunch to the nose":

At this point, unfortunately, it seems clear that the Windows 8 launch not only failed to provide a positive boost to the PC market, but appears to have slowed the market. While some consumers appreciate the new form factors and touch capabilities of Windows 8, the radical changes to the UI, removal of the familiar Start button, and the costs associated with touch have made PCs a less attractive alternative to dedicated tablets and other competitive devices. Microsoft will have to make some very tough decisions moving forward if it wants to help reinvigorate the PC market.
Both Windows 8 and Windows RT are unfamiliar iterations of the all-too-familiar Windows operating system. (It's worth noting that if Windows 8 were essentially Windows 7 with a few new features analysts and pundits would likely blame the operating system's woes on its being too similar to its predecessors. Microsoft can't win.) They represent the beginning of a changing Microsoft, a Microsoft that builds its own hardware, that has finally begun to take smartphones and tablets seriously, that has grown weary of the desktop of old.

Windows, like Microsoft and the rest of the computing industry, is changing. What we're seeing now is a transitionary operating system that is simply laying the foundation for future versions of Microsoft's operating systems. That's why Windows 8 is simultaneously killing the PC and matching the sales of its record-setting predecessor. It could be why Microsoft is so committed to Windows RT despite the negative reaction from pundits, reviewers, and manufacturers, too.

The more interesting issue is whether Windows' struggle to find itself and determine its future is the result of an adolescent operating system struggling to join a maturing, changing market or the midlife crisis of an aging product that's trying too hard to recreate itself and its glory days.