Windows 10 Pro OEM Activation Fails with 0xC004C003 and 0x803FA067 After Repair Install (Dell Latitude 5280)

Naveen Kumar.M 0 Reputation points
2026-09-17T15:41:07.9233333+00:00

I have a Dell Latitude 5280 (Service Tag: ********3H2). Windows 10 Pro (22H2) is installed. The BIOS OEM key is detected, but activation fails with error 0xC004C003 and 0x803FA067 after a repair install. I already tried the Activation Troubleshooter, slui 4, and the Microsoft Product Activation Portal, but it says "Not a valid product." Please verify and restore my OEM activation.

Windows for home | Windows 10 | Licensing and activation
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  1. DaveM121 932.4K Reputation points Independent Advisor
    2026-09-17T16:18:24.72+00:00

    1

    Open the Settings App, go to System - About, ensure the same version (Home or Pro) of Windows is listed there as was previously activated on your laptop.

    2

    If so, click your Start Button, then just type cmd and on the resulting list, right click Command Prompt and select 'Run as Administrator.

    Run this command in Command Prompt and press Enter, to try to reactivate the OEM licence.

    slmgr /rilc

    Then, close Command Prompt and Restart your laptop, then check if Windows is activated, if not, try using the Troubleshooter again.

    3

    If Windows is still not activated.

    Download the free ShowKeyPlus app from the Microsoft Store.

    Please provide a screenshot of that app window and please hide your product key in the screenshot.

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