Final update Microsoft's activation servers appear to be on the blink this morning – some Windows 10 users woke up to find their Pro systems have, er, gone Home.

Twitter user Matt Wadley was one of the first out of the gate, complaining that following an update to the freshly released Insider build of next year's Windows, his machine suddenly thought it had a Windows 10 Home licence.

After updating to Insider Build 18277 my Windows 10 digital license became invalid. I don't understand! I've always installed Insider builds and retail builds on this machine and never had an activation problems. No hardware changes, nothing has changed. I don't know what to do. pic.twitter.com/CtAowTLDTr — Matt 🇦🇺🇨🇦 (@Matthew_Wadley) November 8, 2018

While Insider build 18277, which appeared yesterday, contains lots of goodies, including improvements to Focus Assist to stop notifications bothering customers using apps in fullscreen mode, improvements to High-DPI, and an intriguing setting to allow users to manage camera and mic settings in Application Guard for Edge, it did not mention anything about borking the machine's licence.

To the relief of the bruised Insider team, but no one else, it soon became apparent that the issue is not just isolated to those brave souls trying out preview code, but over many versions of Windows 10.

The vast majority of issues reported so far appear to be from users who upgraded from a previous version.

One of our three-year-old Lenovo Yogas just decided to throw 0xC004C003 Windows activation error. Windows diagnostic tool says the machine has Windows 10 Home license, but why did they put "8 Pro" sticker under the computer then...? Dumbasses. 😐 — Pena Sarajärvi (@penasarajarvi) November 8, 2018

However, some users are also reporting issues with fresh installs.

According to those able to get hold of Microsoft's call centres, the advice is to wait a while and the problem should fix itself, indicating something has gone awry on the licensing servers, and engineers are currently scrambling to fix it. Your machine should be usable in the meantime.

The Register contacted Microsoft to learn more, and we will update if there is a response.

Luckily, the problem does not look to be too widespread, which will be small comfort to affected users who, er, might want to join a domain, set up Hyper-V or all of the other goodies found in Windows 10 Pro. ®

Updated to add at 1220 UTC

While there remains no official statement from Microsoft on the problem, users have reported that the hardworking support operatives of the Windows giant have warned that there is indeed a "temporary issue" with its activation servers related to the Pro edition. Affected customers are advised to sit tight and wait for a fix. An estimate for when that might be? Anywhere from one to two days. Oh dear.

Updated to add at 2150 UTC

Folks are reporting the licensing issues are fixed. Click on Troubleshoot in the activation error window, and it should resolve itself. You may have to reboot and run Windows Update to nudge it along, we're told.

"We're working to restore product activations for the limited number of affected Windows 10 Pro customers,” Microsoft senior director Jeff Jones told us earlier this evening.

Final update at 0100 UTC

If you can't get rid of the activation error, don't worry, it should clear by itself, a Microsoft spokesman said – now that Redmond's techies have sufficiently bashed their machines with spanners:

A limited number of customers experienced an activation issue that our engineers have now addressed. Affected customers will see resolution over the next 24 hours as the solution is applied automatically. In the meantime, they can continue to use Windows 10 Pro as usual.