What does HRESULT 0x80010128 (CO_E_FAILEDTOQUERYCLIENTBLANKET) mean?

CO_E_FAILEDTOQUERYCLIENTBLANKET

COM could not query the client security blanket

CO_E_FAILEDTOQUERYCLIENTBLANKET is HRESULT 2147549480 (0x80010128) from winerror.h. AllStat describes it as “Unable to obtain the client's security blanket.” In the COM IAccessControl, DCOM client identity, trustee translation, token inspection, security descriptor, ACL, or serialization workflow, the code identifies a specific failure boundary and should not be replaced by a generic COM exception.

The caller should keep CO_E_FAILEDTOQUERYCLIENTBLANKET intact through logging, exception translation, and RPC or language projection boundaries.

Diagnostic sequence

• Capture the raw unsigned value 0x80010128 and symbolic name CO_E_FAILEDTOQUERYCLIENTBLANKET before a language projection, exception wrapper, or generic COM helper replaces it.
• Identify the exact interface, method, callback, activation request, metadata query, access-control operation, or marshaling boundary that returned CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Reconstruct the operation timeline for CO_E_FAILEDTOQUERYCLIENTBLANKET, including object creation, thread or apartment initialization, security setup, callbacks, mutations, shutdown, and cleanup.
• Prove the decisive condition: the call context is active and secured, and blanket querying occurs before asynchronous handoff or method return.
• Inspect every output parameter, handle, interface pointer, token, SID, ACL, stream, buffer, server-side object, or asynchronous result produced before CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Reproduce CO_E_FAILEDTOQUERYCLIENTBLANKET with the smallest safe input, change only the suspected precondition, and verify that both the HRESULT and postcondition change as predicted.

Where it is encountered

• CO_E_FAILEDTOQUERYCLIENTBLANKET can be returned during IAccessControl initialization, access checks, owner/trustee processing, and serialized ACL persistence. For CO_E_FAILEDTOQUERYCLIENTBLANKET, record the interface, method, component version, thread, apartment, process, and correlation ID.
• CO_E_FAILEDTOQUERYCLIENTBLANKET can be returned during server-side DCOM impersonation, client blanket inspection, token and SID lookup. For CO_E_FAILEDTOQUERYCLIENTBLANKET, record the interface, method, component version, thread, apartment, process, and correlation ID.
• CO_E_FAILEDTOQUERYCLIENTBLANKET can be returned during security descriptor construction, DACL canonicalization, file-backed policy storage, or legacy NetAccess migration. For CO_E_FAILEDTOQUERYCLIENTBLANKET, record the interface, method, component version, thread, apartment, process, and correlation ID.

The immediate focus for CO_E_FAILEDTOQUERYCLIENTBLANKET is server authorization or auditing that calls <code>CoQueryClientBlanket</code> but cannot retrieve authentication service, principal, level, capabilities, or identity. Keep CO_E_FAILEDTOQUERYCLIENTBLANKET attached to that operation; the same numeric severity outside the owning API does not supply enough context.

Decisive interpretation boundary

Before choosing recovery, verify that the call context is active and secured, and blanket querying occurs before asynchronous handoff or method return. The decisive boundary for CO_E_FAILEDTOQUERYCLIENTBLANKET determines whether the same object can continue, a new object is required, or policy must change.

For CO_E_FAILEDTOQUERYCLIENTBLANKET, also confirm that all observed objects, tokens, buffers, proxies, metadata files, or ACLs belong to the current operation generation and were not retained from an earlier attempt.

Evidence and telemetry

• Preserve authentication service and authorization service for CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Preserve server principal for CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Preserve authentication and impersonation levels for CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Preserve EOAC capabilities for CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Preserve call timing and worker handoff for CO_E_FAILEDTOQUERYCLIENTBLANKET.

For CO_E_FAILEDTOQUERYCLIENTBLANKET, also record UTC time, process and thread IDs, apartment type, component version, security or package identity where relevant, and a correlation ID. For CO_E_FAILEDTOQUERYCLIENTBLANKET, use hashes, lengths, GUIDs, and SID strings rather than logging confidential payloads or credentials.

Difference from nearby HRESULTs

CO_E_FAILEDTOQUERYCLIENTBLANKET concerns binding metadata; CO_E_FAILEDTOGETSECCTX is broader failure to obtain the server security context.

A support tool discussing CO_E_FAILEDTOQUERYCLIENTBLANKET should name the neighboring result only after the originating API and decisive state are known.

Correct handling and recovery

Inspect the binding and call timing, keep the query inside the server method, and reject identity-sensitive work when blanket details are unavailable.

Backoff alone is not a repair for CO_E_FAILEDTOQUERYCLIENTBLANKET; a measurable state or configuration transition must justify another attempt.

Practical scenario

A server queues authorization to a worker then queries the client blanket there. It captures the approved blanket fields during the original call.

A regression test should reproduce CO_E_FAILEDTOQUERYCLIENTBLANKET, assert the raw HRESULT and all relevant outputs, then correct only the decisive condition and verify the intended success or neighboring failure result.

Lifetime, retry, and cleanup rules

After CO_E_FAILEDTOQUERYCLIENTBLANKET, determine whether the current object, interface pointer, call context, token, stream, metadata reader, asynchronous operation, or access-control instance remains valid. For CO_E_FAILEDTOQUERYCLIENTBLANKET, release only resources owned by the failing attempt, cancel callbacks through their documented mechanism, and avoid double close, double commit, repeated activation, or replay of a non-idempotent remote method.

The retry policy for CO_E_FAILEDTOQUERYCLIENTBLANKET should state the trigger, maximum attempts, cancellation owner, and reconciliation step for effects that may have completed elsewhere.

Developer and administrator guidance

A support bundle for CO_E_FAILEDTOQUERYCLIENTBLANKET should include first-occurrence logs, interface and component identity, object generation, relevant policy, and safe hashes. For CO_E_FAILEDTOQUERYCLIENTBLANKET, redact credentials, tokens, private metadata, ACL identities, and serialized payload contents.

For CO_E_FAILEDTOQUERYCLIENTBLANKET, change the smallest component, identity, ACL, package, or threading boundary that the evidence identifies, then reproduce the same operation. Define who owns retry, cancellation, cleanup, policy changes, package repair, and user-facing messaging for CO_E_FAILEDTOQUERYCLIENTBLANKET.

References

• Microsoft: IAccessControl — official Microsoft documentation relevant to CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Microsoft: IAccessControl::IsAccessAllowed — official Microsoft documentation relevant to CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Microsoft: AccessCheck — official Microsoft documentation relevant to CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Microsoft: LookupAccountSidW — official Microsoft documentation relevant to CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Microsoft: LookupAccountNameW — official Microsoft documentation relevant to CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Microsoft: access control lists — official Microsoft documentation relevant to CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Microsoft: canonical ACE order — official Microsoft documentation relevant to CO_E_FAILEDTOQUERYCLIENTBLANKET.
• Microsoft: HRESULT values — official Microsoft documentation relevant to CO_E_FAILEDTOQUERYCLIENTBLANKET.

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