ERROR_SOME_NOT_MAPPED - 1301 (0x515)
Some mapping between account names and security IDs was not done.
Updated: Feb 21, 2026
Technical Meaning
The ERROR_SOME_NOT_MAPPED error code, with the numeric value of 1301 and the hexadecimal representation of 0x515, indicates that there was an issue mapping account names to security IDs during a security-related operation.
Error Details
This error typically occurs when a system attempt to map user or group names to their corresponding security identifiers (SIDs) fails for some entries. This can happen in various scenarios involving access control and authentication mechanisms, such as file permissions, registry operations, or network security configurations.
Usage Context
The context in which this error might be encountered includes:
- File system operations where user or group names are used to set or retrieve permissions.
- Registry operations that involve security-related settings.
- Network services and protocols that require mapping of user identities for authentication purposes.
Developer Interpretation
When encountering the ERROR_SOME_NOT_MAPPED error, developers should interpret it as a failure in the mapping process between account names and SIDs. This could be due to various reasons such as incorrect input parameters, missing or invalid entries in security-related databases, or issues with the underlying authentication mechanisms.
Related Errors
ERROR_NO_SUCH_USER(1326): Indicates that a specified user does not exist.ERROR_INVALID_PARAMETER(1208): Suggests that one of the parameters passed to the function is invalid.ERROR_ACCESS_DENIED(5): May indicate that even after mapping, access was denied due to insufficient permissions.
FAQ
Q: What does the ERROR_SOME_NOT_MAPPED error mean?
A: It indicates a failure in mapping some account names to security IDs during an operation involving user or group authentication and authorization.
Q: How can I troubleshoot this issue?
A: Review the context of the operation, validate input parameters, ensure that all necessary entries exist in the security-related databases, and check for any issues with the underlying authentication mechanisms.
Summary
The ERROR_SOME_NOT_MAPPED error code signifies a failure in mapping some account names to their corresponding SIDs. Developers should focus on validating inputs and ensuring that all required security-related data is correctly configured.