A glitch with Microsoft’s activation servers appears to be disrupting many users's PCs, as Windows 10 erroneously reports their systems as either un-activated or downgraded from Windows 10 Pro to Windows 10 Home.

Users are advised to ignore the Windows messages and wait for the problem to resolve itself, according to postings in Microsoft’s support forums. If those forum postings are accurate, however, the problem could take a few days to resolve.

Microsoft has acknowledged the problem. “We’re working to restore product activations for the limited number of affected Windows 10 Pro customers,' Jeff Jones, a senior director at Microsoft, said in a statement.

At about 4:49 PM, Microsoft issued an update: '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.”

According to users, the Windows activation troubleshooter may report that user PCs may be licensed for Windows 10 Home, even when a valid Windows 10 Pro license is tied to the account on the Windows 10 PC. Windows may also report that the PC’s Windows license isn’t valid at all, and needs to be activated within Windows. (The latter scenario is in place on the PC I’m using right now.)

What's going on?

“Sumit,” a Windows Insider MVP, wrote that Microsoft Chat support had reported a widespread issue, via another user:

“Microsoft has just released an Emerging issue announcement about current activation issue related to Pro edition recently,” according to the message. “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.”

The problem has prevented some users from upgrading from Windows 10 Home to Pro, and worried others that they may have involuntarily purchased a fraudulent license key. Microsoft’s support forums are filled with complaints and concerns from users, without an official response from Microsoft.

Microsoft does seem to be working on the problem, though. If you go to Settings > Update & Security > Activation, you’ll see a blue Troubleshooter link at the bottom of the page. Click it, and Microsoft will attempt to discover the source of the problem. Fortunately, in my case, it worked—though there's no guarantee you’ll have the same luck, unfortunately.

Why this matters: Although this may end up being all for naught, Microsoft certainly doesn’t need any showstopping bugs right about now. Microsoft’s Windows 10 October 2018 Update has yet to ship (it’s now early November, of course) and the company has come under fire for shipping new features without ensuring they’ll work correctly. Telling users that their PC is unlicensed, or that they can’t get all the features of Windows 10 Pro that they paid for? Absolutely no one needs that stress right now.

Updated at 4:50 PM with additional comment from Microsoft.

Windows doesn’t display your PC’s serial number anywhere in its interface, and neither do popular system information tools. But you can often find a PC’s serial number with a simple command, a peek in your BIOS, or on the hardware itself.

Run the WMIC Command

Open a Command Prompt window to get started. On Windows 10 or 8, right-click the Start button and select “Command Prompt”. On Windows 7, press Windows + R, type “cmd” into the Run dialog, and then press Enter.

At the Command Prompt, type the following command and then press Enter:

You’ll see the computer’s serial number displayed beneath the text “SerialNumber”. This command uses the Windows Management Instrumentation Command-line (WMIC) tool to pull the system’s serial number from its BIOS.

If you don’t see your PC’s serial number, blame your PC’s manufacturer. The number will only appear here if the PC manufacturer saved it to your computer’s BIOS or UEFI firmware. PC manufacturers don’t always fill in the number properly. In that case, you’ll see something like “0” or “To be filled by O.E.M.” instead of an actual serial number.

RELATED:How to Check Your Motherboard Model Number on Your Windows PC

This is also true if you built your own PC because the PC itself won’t have a serial number. However, you can look up the serial number of your motherboard and other components.

Check the BIOS

You may also be able to find the serial number in the BIOS or UEFI firmware settings screen. This technique won’t get you a serial number if the wmic command didn’t, since the command pulls the serial number from the BIOS. However, checking the BIOS could be helpful if you can’t actually sign into Windows to run the wmic command.

RELATED:What Does a PC’s BIOS Do, and When Should I Use It?

Access the BIOS or UEFI firmware settings screen and look around for a “Serial Number” somewhere on a system information screen. It’ll be in a different place on different PCs, but you can usually find it somewhere on the “Main” or “System” screen.

Find the Serial Number On the PC’s Hardware, Box, or Elsewhere

If you don’t see a serial number after running the wmic command—or if you just can’t turn the PC on or don’t have access to it—there are several other places you might find the serial number:

• If you have a laptop, flip it over. On some laptops, you’ll see the number on a sticker. On others, you’ll see the number printed directly on the metal or plastic the laptop is made from. If your laptop has a removable battery, the serial number is sometimes on a sticker inside the battery compartment, under the battery.
• If you have a desktop PC, look at the back, top, or side of the case for some sort of sticker. The number may also be on a sticker inside the case, so you might have to open it up.
• If you can’t find the serial number on the PC itself, look online for instructions specific to your model. The manufacturer’s website should tell you exactly where to look.
• If you registered your PC with the manufacturer or received warranty service, the serial number should be included in the registration documentation, warranty service receipt, or email confirmation for the service.

• If you still have the original product box, it usually has the serial number printed on it—often on the same sticker with the bar code.
• If you purchased the PC online or in store, the serial number may be printed on the physical or email receipt you received.

And if you just can’t find your serial number at all, don’t give up hope. If you have proof of purchase, the manufacturer still may be able to help you with whatever service you need and may even be able to find out the serial number for you.