Even so, Microsoft has sold more than 60 million Windows 8 licenses in its first 10 weeks, Reller said, calling that "roughly in line" with Windows 7 at the same point after its 2009 release. At that time, Microsoft told investors that the sale of 60 million Windows 7 licenses was a single-quarter record.
Reller's description of Windows 8 sales -- defined as licenses sold to computer makers for installation in their new PCs, plus cheaper upgrades sold direct to customers -- was the same as when she spoke at a Credit Suisse-hosted conference in late November. Then too, she used "roughly in line" to compare the new OS with its precursor.
Within the 40 million of November and the 60 million of this week are an unknown number of licenses on PCs that have been built and shipped, but not yet sold to customers, analysts have said. Without system sales figures from Microsoft's OEM partners or Microsoft itself, it is impossible to tell how many devices with already purchased licenses are not yet in customers' hands.
Some estimates and metrics have hinted that the number is considerable: The NPD Group, which tracks retail sales in the U.S., said PC sales for the holidays were down 11% compared to the same period in 2011.
Meanwhile, recent data from Web analytics company Net Applications put Windows 8 on a slower uptake pace than either Windows 7 or Windows Vista, the latter the 2007 edition that has been decreed a rare Microsoft flop. Through its first two months of availability, Windows 8 collected less than a third of the online usage share Windows 7 had at the same stage in its release, and was slightly behind even Vista.
But Reller's explanation of Windows 8 sluggish retail sales -- that touch-ready devices were in short supply -- jibes with other data, including the NPD Group's, which said five weeks ago that sales of touch-enabled notebooks were one of few bright spots in Windows 8's first four weeks.
It was clear that Microsoft has heard that message.