What does NTSTATUS 0xC01E0400 (STATUS_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED) mean?

 
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STATUS_GRAPHICS_CLIENTVIDPN_NOT_SET STATUS_GRAPHICS_CHILD_DESCRIPTOR_NOT_SUPPORTED

STATUS_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED

The display child is already connected

STATUS_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED is a Windows NTSTATUS value from the graphics/display facility. It belongs to the WDDM kernel display stack rather than to a Win32 GDI error alone, so the useful context is usually the adapter, VidPN object, child device, present path, or primary allocation involved in the call.

This status is about display-adapter child devices: outputs or onboard devices enumerated by the miniport driver. It means the requested operation tried to connect or associate an external device with a child that is already reported as connected.

The usual causes are duplicated hot-plug notifications, a dock or mux transition reported twice, or stale state after sleep/resume. Do not interpret it as a second physical monitor by itself; first confirm whether the child UID and target identity are identical.

What to check

  • Log child UID, target ID, output technology, and the previous connection state.
  • Coalesce duplicate HPD and ACPI indications before building topology changes.
  • Clear stale child connection state during surprise removal or adapter restart.

References


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