Windows 10 had been installed on more than 14 million devices by Thursday evening, a small step toward the company's goal of an installed base of 1 billion.
"While we now have more than 14 million devices running Windows 10, we still have many more upgrades to go before we catch up to each of you that reserved your upgrade," the company said in a blog post at 6:28 p.m. Thursday.
The latest version of Windows saw a bumpy rollout on Wednesday, with problems including a "Something happened" error screen seen during the installation process. Other issues involved downloading apps from the Windows Store or copying text in the operating system.
Microsoft, however, said it was seeing unprecedented demand for Windows 10 with reviews and customer feedback "overwhelmingly positive around the globe."
The company assured users who reserved their upgrades that they would be notified once the operating system has been downloaded to their PCs.
Windows 10 has been hailed as a return to tried-and-true desktop interface design. While it reintroduces the Start Menu of previous incarnations of Windows, its new features include a face-recognition system in lieu of passwords, the voice-based Cortana personal assistant, Task View, which allows multiple apps across multiple virtual desktops, and streaming for the Xbox One game console.
Microsoft aims to get Windows 10 installed on 1 billion devices over the next few years. The company wants to position the operating system as an ongoing product that is constantly updated, calling it "Windows as a service."
Tim Hornyak covers Japan and emerging technologies for The IDG News Service. Follow Tim on Twitter at @robotopia.