What does HRESULT 0xC0262400 (ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED) mean?

Status / error code:

Category:

Constant name:

Source:

Facility:

Operating System:

Description:

Specified display adapter child device already has an external device connected to it.

Previous	Next
ERROR_GRAPHICS_CLIENTVIDPN_NOT_SET	ERROR_GRAPHICS_CHILD_DESCRIPTOR_NOT_SUPPORTED

ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED

Interpret the result in its owning layer: graphics specified child already connected

ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED, value 0xC0262400, is produced by child when the child output already has an external device associated with it. The investigation should stay attached to display-child connector occupancy and to the exact generation in which it was obtained.

ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED: A child UID identifies an output of the adapter, not necessarily a permanently attached monitor. For ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED, Presence and descriptor capability must be re-evaluated after hot-plug. For ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED, the built-in one-line message identifies the immediate result; diagnosis also needs the producing API, object ownership and the display generation current at the time.

Capture before recreating objects

Capture item	Why it matters for `ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED`
Current graph state	display-adapter child, monitor PDO and connector-presence state
Supporting trace	child UID, HPD awareness, monitor descriptor support, PnP events and connector telemetry
Object identity	display-child connector occupancy
Rejected boundary	the child output already has an external device associated with it
Decisive capture	child UID, connector, previous arrival event, monitor PDO and attempted association

For ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED, preserve the unsigned HRESULT, symbolic name, first failing API and timestamp in one record. If cleanup later fails too, keep that secondary result separately from ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED.

Reproduce one variable at a time

Freeze the ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED generation. Record child UID, connector, previous arrival event, monitor PDO and attempted association. Before diagnosing ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED, do not resize, hot-plug, recreate or release the object under examination.
Run the narrow ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED comparison. disconnect the existing child cleanly before associating the test device. During the ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED comparison, keep every driver, monitor, resource format and unrelated policy unchanged.
Observe the layer after ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED. For ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED, if the exact check passes, record the next HRESULT or visible outcome. A different downstream result shows that the ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED boundary was crossed.
Repeat ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED through a lifecycle transition. For ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED, exercise one relevant resize, mode switch, device recreation, hot-plug or session change and confirm that this result does not reuse stale handles.

The comparison with ERROR_GRAPHICS_MONITOR_NOT_CONNECTED is especially useful: ERROR_GRAPHICS_MONITOR_NOT_CONNECTED reports the opposite physical state for a VidPN target. For ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED, recording both names prevents a broad “graphics error” label from merging distinct ownership, capability and lifetime problems.

Recovery contract

Deduplicate hot-plug events and maintain one current external device per child connector. Repair of ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED is complete only when the original call succeeds or returns its documented nonfatal status and the same lifetime test remains correct after a second display transition.

The ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED trace identifies one producing API and one current graphics object, rather than only the final UI symptom.
The passing run changes exactly the condition described for ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED; unrelated adapter, monitor and application state remains unchanged.
For ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED, debug-layer, ETW or driver diagnostics no longer report the rejected display-child connector occupancy contract during the same scenario.
The application handles recurrence of ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED without an unbounded retry loop, leaked resource, duplicate composition target or stale topology handle.

Implementation notes for `ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED`

For ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED, log child UID, HPD awareness, monitor descriptor support, PnP events and connector telemetry. When the ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED path returns a count, size, status flag or replacement object, retain it even on a nonfatal result because it can direct the next call.

A production fallback for ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED should be explicit: pause rendering, re-enumerate, rebuild one cache entry, recreate a device, or decline a protected path only when this layer calls for that action. Reinstalling every display component, deleting all caches or forcing a resolution change is not an evidence-based fix for ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED.

Technical references

Microsoft: Child device enumeration — background for the display-child connector occupancy boundary involved in ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED.
Microsoft: Monitor child devices — background for the display-child connector occupancy boundary involved in ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED.
Microsoft: Introduction to VidPNs — background for the display-child connector occupancy boundary involved in ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED.
Microsoft: Graphics error codes — background for the display-child connector occupancy boundary involved in ERROR_GRAPHICS_SPECIFIED_CHILD_ALREADY_CONNECTED.

Looking for a different code? Search another status or error code.