Many long-time Windows users avoided Windows 8.1, but it appears they are much more enthusiastic about Windows 10. In just 24 hours of availability, the new upgrade saw 14 million installs worldwide.

“We’re humbled and grateful to see the response to Windows 10,” writes Microsoft’s Yusuf Mehdi on the Windows Blog. “We have seen unprecedented demand for Windows 10, with reviews and customer feedback overwhelmingly positive around the globe.”

Windows 10 made its public debut in 190 countries on July 29, and it’s the first Windows upgrade that’s free for the first year (providing you’re upgrading from Windows 7 or Windows 8.1). Fans have been keen to take advantage of that offer, and 14 million of them upgraded their machines on day one.

That figure may have been even bigger, but Microsoft has had to rollout Windows 10 in phases to ensure that the upgrade process is as smooth as possible for everyone. The software giant promises, however, that it is working around the clock to deliver the update to all as quickly as possible.

“We are grateful for your excitement and enthusiasm and we appreciate your patience over the days and weeks ahead as we carefully roll out Windows 10 in phases to all of you that have reserved,” Mehdi adds.

Windows 10 brings a whole host of improvements and new features, including integrated Cortana, a new Start menu, a user interface overhaul, and the ability to stream your Xbox One games to PC. It also brings the Windows desktop and Windows Phone platforms together for the first time.

If you haven’t yet reserved your Windows 10 upgrade, you can do so now via the Windows icon in your task bar on Windows 7 and Windows 8.1.