Updated:

Microsoft Corp. today confirmed an issue with its Windows Activation service that has seen some users downgraded from Windows 10 Pro to Windows 10 Home.

The first reports of the issue appeared on Microsoft’s Community Forums and Reddit. Users reported that their licensed installs of Window 10 Pro were telling them that they were not activated and advising them to install Windows 10 Home instead.

In other cases, installs were automatically switched to Windows 10 Home with no user prompting at all.

The problem appears to be widespread across multiple versions of Windows 10, including insider beta releases and non-updated systems but there appears to be one common thread: In nearly all cases, users affected had obtained their licenses through a free upgrade path previously offered by Microsoft.

“All of a sudden after years of having this key which was from Windows 8 Pro then migrated to Windows 10 for free, I got a notification saying my key is Windows 10 Home version and that I need to install it.. wtf is going on?,” one user wrote on Reddit.

Making matters worse, ZDNet reported, some users claim to have contacted Microsoft support and were told incorrectly that they needed to repurchase licenses or somehow obtain new product keys. Others were told simply to wait awhile and see if the problem would fix itself.

Microsoft’s messaging over the issue has been a bit all over the place, though a Microsoft support team member did write this on a support forum:

“Microsoft has just released an Emerging issue announcement about current activation issue related to Pro edition recently. This happens in Japan, Korea, American and many other countries. I am very sorry to inform you that there is a temporary issue with Microsoft’s activation server at the moment and some customers might experience this issue where Windows is displayed as not activated.

“Our engineers are working tirelessly to resolve this issue and it is expected to be corrected within one to two business days.”

There are some limited reports as of 7:30 p.m. EST that the problem may have been resolved for some users, but others are still saying that the problem remains.

Update: Microsoft said in a statement, reported by ZDNet at 9 p.m. EST, that it had rectified the issue and affected customers “will see resolution over the next 24 hours as the solution is applied automatically.”

Photo: Air Force Space Command