Speaking at the Credit Suisse 2012 Annual Technology Conference, Tami Reller, chief marketing officer and chief financial officer for Windows, said this was just the start for Windows 8.
"The journey is just beginning, but I am pleased to announce today that we have sold 40 million Windows 8 licenses so far," she said.
In a post on the official Windows 8 blog, Microsoft's communications manager Brandon LeBlanc said early adoptions have been assisted by the easy upgrade process and Windows 8's compatibility with existing Windows 7 PCs.
"Windows 8 is outpacing Windows 7 in terms of upgrades," he wrote. "We built Windows 8 to work great on existing Windows 7 PCs. And we also set out to make upgrading from Windows 7 to Windows 8 super easy."
The two pieces of positive news to emerge from Microsoft's Redmond base gives the company an opportunity to put a much-needed positive spin on the Windows 8 launch.
Despite widespread critical acclaim for its new approach, recent reports have suggested than less than one per cent of all PCs are currently running Windows 8.