What does NTSTATUS 0xC0000078 (STATUS_INVALID_SID) mean?

STATUS_INVALID_SID

The SID bytes do not form a valid security identifier

STATUS_INVALID_SID is a structural validation failure. Windows was given data expected to be a SID, but the revision, subauthority count, total length, or surrounding buffer does not describe a valid SID object. This is different from a valid SID that cannot be mapped to an account.

What to inspect

• Preserve the API that consumed the SID, the buffer length, and the original bytes before any string conversion.
• Use IsValidSid before dereferencing SID fields and GetLengthSid only after validation succeeds.
• If the SID was serialized or received over IPC, verify structure packing, truncation, byte count, and lifetime of the backing buffer.

Recovery boundary

Reconstruct the SID from an authoritative account or security-descriptor source. Changing permissions or domain membership cannot repair malformed SID bytes.

References

• Microsoft Open Specifications: NTSTATUS values
• Microsoft: Using NTSTATUS values