Back in December 2025, Microsoft quietly reworked the telephone activation process for Windows, Office, Server, and Remote Desktop Services products, with no announcement and no fanfare. Customers who rely on this process for offline devices, air-gapped systems, or downgrade scenarios started noticing that the old phone number simply stopped working. I’ve gotten enough questions about it that it’s time to walk through exactly what changed, why it changed, and how to get through it the first time.
The short version: the phone call is gone, but the capability is not. Microsoft has moved the whole process to a web portal. I’ve been calling it the “portal activation process” since Microsoft hasn’t given it an official new name yet. Here’s what you need to know.
Why Do You Still Need This Process?
Telephone activation (now portal activation) isn’t something most users ever touch, but it’s essential for a specific set of scenarios that are common in the Windows IoT and embedded world:
- Downgrading a product to an older version using a key that has already been previously activated
- Activating an offline or air-gapped device that has no internet connectivity
Both are everyday realities for OEMs and embedded customers, so this isn’t an edge case; it’s a process many of you will experience repeatedly.
Step 1: Start the Process With slui 4
Nothing has changed on the device side to kick things off. Open the Run prompt and type:
slui 4
SLUI stands for Software Licensing User Interface, and this command has always triggered the telephone activation screen. It will still display a phone number on screen, but don’t bother dialing it. Calling that number now just gets you a recording directing you to the portal at https://aka.ms/aoh .
The important thing to grab from this screen is your Installation ID. That’s the number you’ll carry over to the portal in the next step. If your device is genuinely offline, you’ll need a second computer or a phone to continue, something to keep in mind if you support customers working in secure areas where stepping out to get online isn’t simple.
Step 2: Sign In to the Portal
This is the part that trips people up. When you get to the portal, Microsoft now requires you to sign in. This is new; in the past, telephone activation was essentially anonymous.
To be clear about what this sign-in does and doesn’t do: your login is not tied to the license itself. It’s tied to tracking the number of activations you personally perform. If you’re doing this for normal, legitimate reasons, there’s nothing to worry about. If you’re running thousands of activations, don’t be surprised if Microsoft reaches out to ask why.
The screen you’ll land on can look like it’s asking for a government tenant or a government Azure cloud login. It is not. You just need a standard Entra ID (formerly Microsoft account) to sign in. Ignore the government tenant option, and click through to proceed with a normal sign-in.
Step 3: Choose “Activate a Microsoft Product”
Once you’re signed in, you’ll see an option for volume license key management; skip that. You want “Activate a Microsoft Product.” From there, you’ll see the full family of supported products:
- Windows
- Office
- Server
- Remote Desktop Services
This list also covers the Windows IoT lineup, Windows IoT Server, Windows IoT client, and the Office LTSC products, even though they aren’t named.
Choosing Windows opens the full version history, including legacy operating systems like Windows 8.1, 8, 7, Vista, and XP. Since Windows licenses are perpetual, it’s not unusual to be activating a much older OS under downgrade rights, and the portal accounts for that.
Step 4: Enter the Installation ID
This step has a quirky UI element worth calling out ahead of time. The screen presents six boxes, but you can’t click on them individually to type. Instead, click into the top field and start typing your Installation ID. Once you’ve entered at least 14 digits, the system automatically populates the six boxes below.
After the full Installation ID is entered, the portal generates a Confirmation ID.
Step 5: Finish Activation on the Device
Take that Confirmation ID back to the original device and enter it into the activation screen. If everything lines up, you’ll see confirmation that the product has been successfully activated.
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Windows Champ Tip: The whole workflow still supports downgrade rights and offline activation exactly like before; the only real difference is that you’re now typing into a browser instead of talking to a phone tree and hunting for the right country code. |
What This Means for Offline and Air-Gapped Environments
For most customers, this is a net improvement. You no longer must navigate an automated phone system or figure out international dialing codes. But for organizations with secure or restricted areas, the sign-in requirement adds a wrinkle: someone may now need to physically leave that secure space to reach a second device with internet access and a browser, rather than simply picking up a phone from within it. It’s worth building that extra step into your activation procedures if it applies to your environment.
To Summarize
Microsoft removed the phone call from telephone activation in December 2025 without any formal announcement, replacing it with a web-based portal. The process still supports the same core scenarios, downgrade rights, and offline/air-gapped activation, but now requires signing in with an Entra ID, which Microsoft uses to track activation volume rather than to tie the login to a specific license. Once you know to expect the sign-in screen and the quirky Installation ID entry field, the new process is quicker than the old one.
FAQs
Do I still need to call a phone number?
No. Calling the number shown on the slui 4 screen now returns a recording directing you to the web portal instead.
Will I lose the ability to activate offline or air-gapped devices?
No. Offline and air-gapped activation is still fully supported; you just complete the portal steps on a second, internet-connected device or phone rather than the offline device itself.
Does signing in link my account to the software license?
No. Your sign-in is used only to track how many activations you’re performing, not to associate your identity with the license itself.
Do I need a government tenant or government Azure account to sign in?
No. A standard Entra ID (formerly a Microsoft account) is all that’s required. The government tenant option on the sign-in screen does not apply to this process.
Which products does the new portal support?
Windows (including legacy versions back through XP), Office, Server, and Remote Desktop Services, which also covers the Windows IoT and Office LTSC product lines.
Questions? If you have additional questions on the Microsoft activation process or on Windows IoT in general, reach out to the Arrow Microsoft IoT team at windowsiot@arrow.com or visit Arrow.com/winiot. We will respond to your inquiry within 24 hours.
