Microsoft started hump day on solid footing by announcing that there are now more than 500 million active devices worldwide running Windows 10. CEO Satya Nadella revealed the milestone during his keynote speech to kick off the annual Build developer conference in Seattle.

The Redmond-based company initially set out to get Windows 10 on a billion devices within the first three years but conceded last July that it may have been a bit too ambitious. Still, adoption of its operating system is forging ahead at a respectable rate.

Windows 10 at the end of March 2016 had just north of 200 million active device installs. That figure climbed to 300 million as of May 5, 2016, before hitting 400 million this past September. Looking at the latest numbers, we see that it has taken around seven months or so to add an additional 100 million installations.

Sources reportedly familiar with the company’s plans tell The Verge that Microsoft is loosely targeting 550 million active devices by the end of June and 575 million by the end of September.

Unfortunately for Microsoft, only around 141 million of its 500 million Windows 10 devices – roughly 28 percent – utilize Cortana on a monthly basis. Worse yet, as PCWorld highlights, it’s unclear if those using Microsoft’s digital assistant are relying on it for questions, setting reminders or simply using the search box as a generic Start Menu replacement.

In related news, Microsoft said 100 million people per month are using Office 365’s commercial subscription services. Furthermore, 90 percent of Fortune 500 companies are now utilizing a portion of the Microsoft cloud.

Microsoft Build 2017 runs through May 12 at the Washington State Convention Center.