Security Systems Error Code
Systems & Devices
Security Systems
0xC0000064 | No such user
Industry
Systems & Devices
Canonical
/systems/security-systems/error-codes/0xc0000064/
Last Updated
Feb 27, 2026
Summary
The specified user name does not exist or could not be found by the authentication system.
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What This Code Means
0xC0000064 is an NTSTATUS authentication result commonly observed in Windows security logs and authentication traces. It indicates the username provided could not be matched to an account in the authentication database (local SAM or directory service).
Where Users Usually See This Code
- Windows Security event logs (failed logons)
- RDP, SMB, or domain authentication attempts
- SIEM alerts and authentication monitoring
Why This Code Appears
- Username mistyped
- Account was deleted/renamed
- Wrong domain/realm used
What Typically Happens Next
- Logon fails and access is denied
What This Code Is Not
- It is not a password-correctness indicator
- It is not proof of an intrusion by itself
Troubleshooting Checklist
- □ Verify the username and domain/tenant context
- □ Confirm the account exists and is enabled
- □ Review the source host and protocol to determine whether this is user error or automated traffic
Notes And Edge Cases
Automated scans and misconfigured services can generate many “no such user” events.
Related Codes
8 links
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