What does HRESULT 0xC00D11BB (NS_E_WMP_INVALID_PROTOCOL) mean?

Status / error code:

Category:

Constant name:

Source:

Facility:

Operating System:

Description:

Windows Media Player cannot play the file because the specified protocol is not supported. If you typed a URL in the Open URL dialog box, try using a different transport protocol (for example, "http:" or "rtsp:").%0

Previous	Next
NS_E_WMP_AUDIO_HW_PROBLEM	NS_E_WMP_INVALID_LIBRARY_ADD

NS_E_WMP_INVALID_PROTOCOL

Diagnosing NS_E_WMP_INVALID_PROTOCOL in the Windows Media Player playback path

NS_E_WMP_INVALID_PROTOCOL (0xC00D11BB) is returned when the URL explicitly requests a transport scheme the Player does not support in the current configuration.

Trace path or URL resolution, proxy and network selection, parser and codec discovery, graph construction, rendering and optional DRM as separate layers. Record what the Player had already completed because later retries often replace the original evidence. The specific rejected condition is the URL explicitly requests a transport scheme the Player does not support in the current configuration.

Playback boundary

AllStat already supplies the standard user-facing description for this HRESULT; this custom block instead isolates the additional technical boundary. Earlier success in file lookup, network connection, parser creation or graph construction does not prove that the later the operation is valid.

Case-specific checkpoint: raw URL, parsed scheme, supported protocol list, enabled settings and object-model proxy record. The controlled comparison for this HRESULT is: replace only the scheme with a documented supported transport for the same server resource.

Closest distinction: NS_E_WMP_PROTOCOL_PROBLEM can occur after a supported scheme is selected but cannot be used successfully.

Capture the first failing layer

Capture	Why it matters for this HRESULT
Object or resource	raw URL, parsed scheme, supported protocol list, enabled settings and object-model proxy record
State snapshot	Record the Player openState/playState or operation phase, object identity and exact timestamp when this result was returned.
First lower result	Keep the earliest Win32, Winsock, COM, parser, codec, DRM or device result that appears before this result.
Comparison record	Use one known-good case that follows the same API, protocol and component path while changing only the rejected precondition.

Controlled playback comparison

Start from the original call and log 0xC00D11BB together with its object and operation phase.
Collect raw URL, parsed scheme, supported protocol list, enabled settings and object-model proxy record before changing the machine.
Use this single-variable test: replace only the scheme with a documented supported transport for the same server resource.
repeat on a fresh object if the original predates a configuration, device or resource change.
validate the expected next operation, not just initial open or object creation.

How to interpret the retest

Retest outcome	Interpretation
Same this result on the same object	The governing state or value is unchanged, or the caller is reusing an object created before the relevant change.
Fresh object succeeds	Lifetime, cached configuration or stale playlist/graph state contributed to this result.
A later HRESULT appears	The rejected condition — the URL explicitly requests a transport scheme the Player does not support in the current configuration — was cleared for this HRESULT; diagnose the new code at its own layer.
Only one item or endpoint fails for this HRESULT	The evidence favors resource-specific data, rights, routing or device state rather than a global Player failure.

Actions that obscure the cause

adding the scheme name as a file association.
Do not discard the first occurrence by repeatedly invoking Play, open, save or retry; later events can replace its original state.
do not publish credentials, private URLs, license material or complete protected-content headers; retain only redacted identifiers, lengths, hashes and protocol fields.

Technical references

Retain before-and-after evidence for this HRESULT so object recreation or content replacement is not mistaken for random retry success.

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