Microsoft clarifies Ballmer's claims of massive Windows 8 adoption

But that's not accurate. "Metro-style apps will only run on Windows 8 devices, so it seems to me that the number of XP, Vista and Windows 7 users is irrelevant."

Helm also criticized the numbers game Microsoft plays.

If the company counts licenses to come up with its projections, then by Microsoft's rules there's a host of PCs that the company can slip into the "Windows 8" column. The desktops, laptops, tablets and ultrabooks equipped with Windows 8 or even Windows RT, are just part of Microsoft's total, said Helm.

"All existing PCs that have Software Assurance coverage on Windows 7 Professional as of the Windows 8 launch ... [are entitled] to run Windows 8," Helm said. "[And] all PCs that ship with rights to Windows 8 under a technology guarantee program, something that Microsoft has done with earlier versions of Windows, they're counted as Windows 8 licenses too."

Microsoft hasn't announced an upgrade deal -- what Helm called a "technology guarantee" -- but will reportedly kick off the program the first week of June, when it starts offering a $15 upgrade to Windows 8 Pro for buyers of Windows 7 PCs.

"So if a technology guarantee program starts June 1, over half of the Windows PCs that ship in 2012 will 'have' Windows 8," said Helm, showing how Microsoft can easily inflate the number. "But all that is irrelevant for device makers and app developers."

Like Cherry, Helm was certain that what those partners were interested in was the number of Windows 8 users -- thus customers -- not an amorphous pool of licenses, many of which may not be running Windows 8 now or even in the foreseeable future.

In other words, Microsoft's attempt to put Windows 8 in the best light -- at least to developers -- by touting a huge number of PCs able to run the OS is a smokescreen.

"Initially the market for Windows 8 Metro-style applications will be small, [although] it will grow over time," said Cherry. "But it does not start on Day One as the entire base of Windows users."

How fast that installed base converts to running the new OS will be critical, Cherry continued, but he declined to predict how fast that may occur. "There is little history to predict that adoption," Cherry said.

Microsoft has not yet disclosed a ship date for Windows 8, or the availability of Windows 8- and Windows RT-powered devices, but most experts expect an October launch, although some have staked out November instead.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His email address is gkeizer@computerworld.com.

See more by Gregg Keizer on Computerworld.com.

• Microsoft software satisfaction slumps
• Boutique PC seller laughs all the way to the bank on the back of Windows 7
• Dell replays Windows 8 blame card as PC sales slide
• Windows 8 is an enterprise 'non-starter' because IT sees no value in changes
• Windows 8 isn't New Coke, says top Microsoft exec; it's Diet Coke
• Dell slashes its Windows RT tablet price by $200; XPS 10 now sells for $300
• Microsoft votes for free Windows 8.1, collects kudos
• Windows 8 app store fails Top 10 test
• KiraBook review: An ultrabook for the 1%
• Microsoft to squeeze more devs into BUILD

Continuing coverage: Windows 8

Read more about Windows in Computerworld's Windows Topic Center.