Microsoft Enterprise Platforms Support: Windows Server Core Team
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Activation, also known as Microsoft Product Activation or Windows Product Activation, is an anti-piracy technology designed to verify that Microsoft software products are legitimately licensed. Activation works by verifying that the product key—the 25-character code located on your Certificate of Authenticity (usually affixed to your computer) or proof of license label (usually affixed to the installation disc case)—is authentic and is not in use on more personal computers than are permitted by the software license.
Scoping the Issue
What operating system are you trying to activate?
Has the machine been activated in the past?
Have you made any changes to hardware or installed any updates?
Are you being prompted to re-activate or re-enter your product key?
What type of activation are you having a problem with?
Volume License activation?
slmgr.vbs -dlv from KMS host
slmgr.vbs -dlv from KMS client
Key Management Service log from the KMS host
1. Download the MGADiag application from
Click Run or Open when prompted
2. Click Continue. The tool will scan your computer and display your results
3. When the diagnostic check is complete, click Copy to copy your results to the clipboard
4. Paste (CTRL-V) this output into an email or text file.
5. After clicking COPY in step 3 above, an output .CAB file is generated in your C:\MGADiagToolOutput folder with a filename similar to MGADIAGyyyymmddhhmmssnnn.cab. Please include this .CAB file in your email.
Troubleshooting / Resolution: