Windows 10 Pro not activating ESU Licence

Given that Windows Update still shows the system as unsupported, here are a few things to double-check:

Windows Edition Compatibility: ESU licenses are only valid for specific editions like Windows 10 Enterprise or Windows 10 Pro for Workstations. If you're using Windows 10 Pro (standard), it may not be eligible for ESU activation.

ESU Prerequisite Updates: Ensure that all prerequisite updates are installed before applying the ESU key. These include servicing stack updates and the ESU preparation package. You can find the latest list on the Microsoft Learn site.

Activation GUID Usage: The GUID f520e45e-7413-4a34-a497-d2765967d094 is correct for ESU activation, but sometimes running slmgr.vbs /ato without the GUID can help if the system already recognizes the ESU license.

Network and Firewall Settings: If activation is being blocked, check that the system can reach Microsoft’s activation servers. A firewall or proxy might be interfering.

Intune or Scripted Remediation: If you're managing devices at scale, Microsoft Intune or PowerShell-based remediation scripts (like those on GitHub) can help automate and verify ESU activation.

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