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NAP_E_MISSING_SOH
The expected Statement of Health is missing
NAP_E_MISSING_SOH is HRESULT 0x80270002 (signed decimal -2144927742, unsigned decimal 2150039554). AllStat, using winerror.h, describes it as “An SoH was missing from the NAP packet.” The value has failure severity, facility 0x27, and code field 0x0002.
This is a legacy Network Access Protection result: Microsoft states that NAP is unavailable starting with Windows 10 and that current Windows Server releases do not include the former NAP, HRA, and HCAP roles; use the code for supported legacy systems, archived telemetry, compatibility components, or migrations rather than assuming a modern machine should expose the old platform.
Absence of health data, not malformed health data
NAP_E_MISSING_SOH is used when a validation path expects a Statement of Health request but none is available. Microsoft documents a precise SHV behavior: when GetSoHRequest yields a null packet, an ordinary validator should populate a response with this error. An intrusion-detection validator may instead create its own request describing why the client is considered malicious. The code therefore reflects missing input at the SHA-to-SHV contract boundary.
How an SoH can disappear
- The client enforcement path sent a NAP envelope without the SHA-specific SoH that the server-side validator expected.
- A registered SHA was not bound or failed before producing health data, so the system-generated request did not contain normal posture attributes.
- An intermediary filtered an attribute by SystemHealthEntityId or rebuilt a packet while omitting an empty-looking SoH element.
- The SHV queried the request object before the NAP server had associated the intended statement, or used the wrong validation request instance.
- Legacy client and server configuration disagree about which SHAs and SHVs participate in the enforcement scenario.
What to capture
- Record the SystemHealthEntityId requested by the SHV and enumerate the SoH attributes that actually arrived.
- Preserve the napSystemGenerated flag from GetSoHRequest; a system-generated failure packet must be interpreted differently from a normal SHA statement.
- Correlate SHA registration, binding state, NotifySoHChange activity, enforcement-client connection ID, and server validation request ID.
- Log whether other SHAs supplied statements in the same exchange, which separates a component-specific omission from loss of the entire NAP payload.
Tracing the missing statement
- Verify that the SHA is registered with the same numeric health ID that the SHV expects.
- Confirm that the SHA binding initialized successfully and that its GetSoHRequest callback is reached when the NapAgent requests health data.
- Inspect the enforcement transport before and after encapsulation to determine whether the SoH existed on the client but was dropped later.
- On the server, retrieve the request once per documented lifecycle and avoid substituting an unrelated cached validation object.
Difference from nearby NAP results
NAP_E_INVALID_PACKET means bytes are present but invalid. NAP_E_NO_CACHED_SOH is more specific to an SHA that cannot produce fresh health information quickly and has no cached statement to return. NAP_E_NOT_INITIALIZED reports an unbound SHA rather than merely the absence observed by the SHV.
Retry and recovery
Do not manufacture a healthy response. Return or preserve NAP_E_MISSING_SOH so policy can map the component failure explicitly, then restore the SHA registration, binding, or transport path. A new validation is safe after the producer can supply a statement; repeatedly validating the same request object cannot create the missing data.
Practical scenario
A server has an antivirus SHV enabled, but the matching SHA was removed from an older client image. The NAP packet reaches the validator without that health statement. The SHV returns a response containing NAP_E_MISSING_SOH, allowing policy to distinguish unavailable posture data from an antivirus compliance failure.
References
- Microsoft: NAP error constants
- Microsoft: SHV validation contract
- Microsoft: SHA GetSoHRequest callback
- Microsoft: Network Access Protection overview
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