Knowledge

ERROR_DATATYPE_MISMATCH - 1629 (0x65D)

Data supplied is of wrong type.

Updated: Feb 21, 2026

Technical Meaning

The ERROR_DATATYPE_MISMATCH error indicates that a function or operation received data of an incorrect type. This can occur when the expected input parameter is not compatible with the actual data provided.

Error Details

This error typically arises in scenarios where a specific data type is required, but a different type is supplied. For example, if a function expects an integer value and receives a string instead, this error will be triggered.

Usage Context

ERROR_DATATYPE_MISMATCH can occur in various contexts within the Windows API, particularly when dealing with parameters that have strict data type requirements. It is commonly encountered in functions related to file operations, registry manipulation, or other system-level interactions where precise parameter types are necessary for correct operation.

Developer Interpretation

When encountering ERROR_DATATYPE_MISMATCH, developers should ensure that all function calls adhere strictly to the expected data types of their parameters. This includes verifying input values and ensuring that they match the required type specified in the API documentation.

Related Errors

  • Error_INVALID_PARAMETER (0x57)
    • Occurs when a parameter is invalid but not necessarily due to a type mismatch.
  • Error_UNSUPPORTED_TYPE (0x64F)
    • Indicates that an unsupported data type was provided, which may or may not be related to the expected type.

FAQ

Q: Can this error occur in user-mode applications?

A: Yes, ERROR_DATATYPE_MISMATCH can occur in both kernel and user-mode environments where API calls are made with incorrect parameter types.

Q: Is this error always critical for system stability?

A: No, while it may indicate a programming error, the impact on system stability varies. It is generally advisable to correct the issue but does not typically lead to severe system-wide failures.

Summary

ERROR_DATATYPE_MISMATCH serves as a clear indication that data supplied to an API function was of the wrong type. Developers should ensure strict adherence to parameter types when making API calls to avoid this error and maintain the integrity and reliability of their applications.