Dear Anthony M,
Here’s a focused checklist to find why machines still report EOL after the ESU key shows activated.
- Confirm the Windows edition is ESU-eligible (Pro retail versus Pro volume/education/enterprise differences can affect entitlement).
- Verify you installed the ESU product key correctly and activated it on each machine:
- slmgr.vbs /ipk <ESU-MAK-key> then slmgr.vbs /ato and confirm with slmgr.vbs /dlv.
- Ensure the ESU prerequisite updates (the ESU enabling update that Microsoft required for the release year and the latest servicing stack updates) are installed on every PC; missing these updates causes Windows Update to still treat the device as out of support.
- Confirm the monthly ESU quality updates classification is available and that Group Policy or Windows Update for Business policies are not blocking or targeting the devices away from Microsoft Update.
- Check date/time and TLS connectivity to Microsoft Update servers so the system can validate entitlement and receive ESU patches.
- Inspect Windows Update logs and the Event Viewer Application/System logs for errors referencing ESU, entitlement, or license validation around the times you run activation.
- Verify the ESU MAK has remaining activations with your reseller/partner portal if you used MAK rather than an online entitlement; contact your reseller if activations are exhausted.
- Re-run slmgr.vbs /ato and capture the output and the Event ID entries for licensing to correlate failures for a single test machine.
- If you used a KMS host for other activations, ensure your KMS host or proxy isn’t interfering with ESU MAK activation on endpoints.
- As a fallback, test a clean repro on one machine: uninstall any nonessential update blockers, apply the prerequisite ESU update, install the ESU key, activate, and confirm Windows Update now offers ESU security-only updates.
If this helps, please hit “accept answer” — thanks and good luck 🙂
Best regards,
Vivian