What does HRESULT 0xC00E007A (MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST) mean?

MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST

Interpretation

When MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST appears, start with the queue operation and its property arrays rather than with a broad repair of the Message Queuing service. Its diagnostic boundary is directory object has no registered encryption public key. This differs from directory unreachability: the lookup completed and the key attribute was absent.

For MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, encryption capability and message authentication are related but distinct. When diagnosing MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, preserve provider, algorithm, certificate, key-container, and queue authentication/privacy settings rather than collapsing them into one “SSL” diagnosis.

When diagnosing MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, authenticated MSMQ messages combine a sender identity, certificate, private key, hash/signature algorithm, and queue policy. In the MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST path, successful certificate parsing does not prove that the key is accessible to the sending process.

Relevant API contract

When diagnosing MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, queue ACLs, certificate trust, private-key access, provider support, and destination authentication policy are independent. Test the layer named by the evidence. For MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, the code-specific boundary is directory object has no registered encryption public key.

Decisive observations

• Certificate store location and security identity used by the process; associate it explicitly with MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST.
• When diagnosing MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, provider name/type, hash algorithm, and privacy/authentication properties; capture the value before cleanup or retry changes it.
• In the MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST path, whether the failure occurred while preparing, sending, storing, or validating the message; compare it with a known-good call using the same account and queue type.
• For this MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST result, record the queue path or format name, local/remote placement, transactional flag, caller SID, process build, and UTC correlation ID when they apply.

For MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, log certificate thumbprints, provider names, SIDs, GUIDs, lengths, and hashes where useful, but do not log private keys, symmetric keys, credentials, or confidential message bodies.

Troubleshooting workflow

1. Record the unsigned HRESULT, MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, and the native API or COM method before a framework replaces it with a generic exception.
2. When diagnosing MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, verify the postcondition after the failed call: queue existence, message presence, directory object state, transaction outcome, or generated output may differ by result.
3. In the MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST path, capture provider name/type, hash algorithm, and privacy/authentication properties.
4. For this MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST result, capture whether the failure occurred while preparing, sending, storing, or validating the message.
5. Reproduce with the smallest queue/message/property set that still returns MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST; change one precondition at a time.
6. When diagnosing MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, apply the code-specific recovery rule: Register/publish the destination key and allow replication before retrying encrypted sends.

Recovery rules

Register/publish the destination key and allow replication before retrying encrypted sends.

When diagnosing MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, the retry decision must account for side effects that may already exist. In the MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST path, query queue, message, directory, or transaction state first whenever the result leaves completion uncertain.

Differences that matter

In the MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST path, authentication failure is not synonymous with queue access denial. For this MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST result, certificate stores, private keys, providers, signatures, and queue policy must be tested separately. The specific focus for MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST remains directory object has no registered encryption public key.

• In the MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST path, changing queue names, deleting directory objects, or recreating certificates without reconciliation can create a second object while callers still reference the first.
• For this MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST result, A successful test under an interactive administrator account does not prove that the production service account has the same profile, token, directory access, or key permissions.

Practical scenario

A certificate-registration utility encounters MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST. For MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, it tests store and private-key access under the production identity before changing queue security. When diagnosing MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, the acceptance test then changes only the decisive precondition and confirms both the HRESULT and the actual queue/message state.

For MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST, include a negative test for the nearest misleading diagnosis so monitoring and user guidance do not collapse distinct MSMQ failures into one alert.

Sources

• IETF RFC 5280: Internet X.509 PKI certificate profile — source used for the MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST analysis.
• Microsoft: Message Queuing error and information codes — source used for the MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST analysis.
• Microsoft: authenticated MSMQ message with an external certificate — source used for the MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST analysis.
• Microsoft: MSMQMessage object and message properties — source used for the MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST analysis.
• Microsoft: Windows certificate stores — source used for the MQ_ERROR_PUBLIC_KEY_DOES_NOT_EXIST analysis.

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