Did you download Windows 8 Enterprise using your MSDN or TechNet subscription for testing in your lab?  As the full-featured "business edition" of Windows 8, the Enterprise SKU defaults to using corporate Volume License activation on a business network.  On a business network, this process provides a simplified end-user activation experience, because Windows 8 Enterprise automatically determines which servers to activate against using DNS without you needing to manage individual activation keys for each PC.  To learn more about the Windows 8 Volume License activation process on a business network and the new Active Directory-based activation process, click here.

But, what if I'm testing Windows 8 Enterprise in an isolated lab environment?

This VL activation process works well in a business environment to simplify and automate the overall activation experience, but if you're testing Windows 8 Enterprise in an isolated environment, then you'll encounter an error during the activation process and activation will not successfully complete.  This is because your Windows 8 Enterprise PC cannot find the appropriate DNS records to determine how to automatically activate.  But, there's an alternative! In your TechNet and/or MSDN subscription portal, you have the ability to claim a "Multiple Activation Key" (MAK) for activating Windows 8 Enterprise by clicking the "Product Keys" button.  The MAK is an alternative Product Key that doesn't require the same corporate VL activation process on a business network.

Great! I've got my MAK - What do I do now?

To enter your MAK on Windows 8 Enterprise and successfully activate, you can complete one of the following steps:

• Command Line option:
  
  Hit the Windows+R hotkeys to open the Run box and run the following command:
  
  slmgr -ipk xxxxx-xxxxx-xxxxx-xxxxx-xxxxx
   
• GUI option:
  
  Hit the Windows+R hotkeys to open the Run box and run the following command:
  
  slui.exe 3
  
  This command will open the following Dialog Box in which you can manually enter your MAK:

Enter your MAK in the "Product Key" field shown above, click the "Activate" button and you should be good to go!

HTH,

Keith