ERROR_UNEXPECTED_MM_MAP_ERROR - 557 (0x22D)
If an MM error is returned which is not defined in the standard FsRtl filter, it is converted to one of the following errors which is guaranteed to be in the filter. In this case information is lost, however, the filter correctly handles the exception.
Updated: Feb 21, 2026
Technical Meaning
The ERROR_UNEXPECTED_MM_MAP_ERROR error code, with the numeric value of 557 or hexadecimal 0x22D, is encountered when a memory management (MM) error occurs that is not defined within the standard filter provided by FsRtl. This error ensures that any unhandled MM errors are mapped to one of the predefined errors in the FsRtl filter, thereby maintaining consistency and predictability in error handling.
Error Details
When an unexpected MM error is detected, it is converted into a known error code from the FsRtl filter. This conversion process guarantees that all exceptions are handled within the framework but may result in loss of specific information about the original error.
Usage Context
This error typically arises during operations involving memory management and file system interactions where MM errors might occur, such as when handling file mappings or other low-level memory operations.
Developer Interpretation
Developers should interpret this error as an indication that a non-standard MM error has been encountered. The specific nature of the error is lost in translation to a standard FsRtl error code, which may limit the diagnostic information available for troubleshooting.
Related Errors
ERROR_INVALID_PARAMETER(1324)STATUS_INVALID_PARAMETER(0xC000000D)STATUS_UNSUCCESSFUL(0xC0000001)
FAQ
Q: What does the ERROR_UNEXPECTED_MM_MAP_ERROR error indicate?
A: It indicates that an MM error not defined in the standard FsRtl filter has occurred, and it is converted to a known error code.
Q: Can this error be avoided?
A: While specific causes cannot always be prevented, ensuring valid parameters and correct usage context can help mitigate issues leading to unexpected errors.
Summary
The ERROR_UNEXPECTED_MM_MAP_ERROR (557) is an error code that indicates a non-standard MM error has been encountered during operations involving memory management. Developers should treat this as a generic error with limited diagnostic information, focusing on validating parameters and ensuring correct usage context to avoid such errors.