DeviceOK
SearchCheck my device
Home / Errors / Device Manager / Code 40
Windows Device Manager

Code 40: Windows cannot access this hardware because service-key information is missing or incorrect

The driver's registry service information is invalid.

First action

Reinstall the device driver rather than manually editing the registry first.

Use the error code as a Windows device-state clue. It does not by itself identify the exact failed component inside the hardware.

Then verify

Do not stop at the code disappearing

  1. 1

    Scan for hardware changes after uninstalling.

  2. 2

    Escalate to official vendor support if the configuration is repeatedly corrupted.

After Windows reports the device normally, run the matching DeviceOK test when one exists—for example camera, microphone, keyboard, mouse, controller or audio—to confirm the user-facing function works.