Microsoft announced today that it has sold 60 million licenses to Windows 8. This is the second sales update for the new operating system, which has sold slowly compared to the previous release and has thus far disappointed Microsoft internally.

Microsoft’s Tami Reller made the announcement at CES in Las Vegas.

Microsoft announced in late November that it had sold 40 million licenses in Windows 8’s first month. So this figure represents a 20 million license gain in 30 days, which was the average for Windows 7 over its three year lifecycle. (Indeed, Ms. Reller noted that this figure was “roughly in line with where we would have been with Windows 7,” which is another way of putting it.)

I’ve probably written enough about Windows 8 not meeting Microsoft’s expectations and, more recently, not selling well during the 2012 holiday period. But it’s worth noting that this 60 million figure includes what Reller calls “sell-in to OEMs for new PCs,” meaning that many of these Windows 8 units are sitting on as-yet-unsold PCs. Of course, that’s how Microsoft has always measured sales, which is fair, since that’s the point at which it literally makes the sale.

Reller also announced that Microsoft has now has certified over 1,700 devices for Windows 8 and Windows RT. And there’s positive news about the Windows Store as well.  Since the Windows 8 launch, the number of apps in the store has quadrupled, with more than 10,000 new apps added in the last month alone. And users have now download over 100 million apps overall. Not bad for just two months.