How to activate a Windows computer that is not connected to the internet

If you are building a secure computer, then the best approach is to never connect it to the internet. If the operating system on this computer is Windows, then you will have to activate it before you will be able to use it. This article explains how you can activate it by phone.

Windows can't be activated right now

If you try to use the standard Windows activation interface, then you will most probably receive the error Windows can't be activated right now. This makes perfect sense since the activation application tried to connect to Microsoft's activation servers. However, since you are offline, the computer can not connect these servers. It shouldn't even be possible to resolve the DNS names of these servers!

The answer here is to activate the computer by phone. To start the Windows Activation Wizard, click Start, click Run, type slui.exe 4, and then click OK. An alternative approach is to press the Windows+R keyboard combination to open the Run window.
If you are running Windows 8, follow these steps:

  1. Swipe in from the right edge of the screen, and then tap Search. Or, if you are using a mouse, point to the lower-right corner of the screen, and then click Search.
  2. Type slui.exe 4, and then tap or click the displayed icon to open the wizard.

After selecting your country, you are shown one or more phone numbers and series of numbers that your have to type on your phone.

Can't activate windows by phone

It may happen that you get the following error after having typed slui.exe 4: Can't activate windows by phone. It is very likely that you receive this error on an OEM version of Windows or with an Enterprise edition of Windows. The reason for this error is that Windows can't generate the numbers needed for phone activation since you have probably never entered a product key. For example when you install Windows 8 or 8.1 Enterprise, they you are not asked for a product key during the installation. This is because Microsoft allows you to use it for free during a 90-day evaluation period before you have to purchase or enter a product key (license key).

So you first have to change your product key. You can do this by typing the command slui.exe 3. This will bring up a window that allows to enter a product key. After you type your product key, the wizard will try to validate it online. Once again, you are offline or on a stand-alone system, so this connection will fail. Microsoft then presents you with the following error "This key didn't work, please check it and try again, or try a different key". Don't worry about this error. Click "Cancel" to leave the wizard. Even though Windows doesn't tell you this, it has stored the product key somewhere. So if you now try the phone activation wizard again, it will work.

The instructions mentioned above are applicable for the following operating systems:

  • Windows 8.1
  • Windows 8
  • Windows 7
  • Windows Vista
  • Windows Server 2012
  • Windows Server 2008 R2
  • Windows Server 2008


slui.exe is a tool that is present in Windows since Windows Vista. SLUI is short for Software Licensing User Interface.


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