Microsoft spokesman Terry Myerson said that millions had signed up for a free Windows 10 upgrade.

"Soon, we will give a build of Windows 10 to our OEM partners so they can start imaging new devices with Windows 10. The new devices our partners are working on are very exciting, I can't wait to hear your feedback as you get a chance to use them," he said.

 

Soon after, Microsoft will distribute a build of Windows 10 to retailers all over the world, so they can assist their customers with upgrades of newly purchased devices that were originally imaged with Windows 8.1.

Myerson suggests that customers should look for a sticker to be certain that the OEM partner has proactively tested a device for compatibility with Windows 10.

On July 29, Redmond will start rolling out Windows 10 to Windows testers. From there, Microsoft will start notifying reserved systems in waves, slowly scaling up after July 29th.

"If you reserved your copy of Windows 10, we will notify you once our compatibility work confirms you will have a great experience, and Windows 10 has been downloaded on your system," Myerson said.