Knowledge

ERROR_BAD_FORMAT - 11 (0xB)

An attempt was made to load a program with an incorrect format.

Updated: Feb 21, 2026

Technical Meaning

ERROR_BAD_FORMAT is a generic error code indicating that an attempt was made to load a program with an incorrect format. This error typically occurs during the process of loading executable files or dynamic link libraries (DLLs) into memory.

Error Details

The numeric value 11 and its hexadecimal representation 0xB are used to denote this specific error condition within the Windows operating system. The error is returned by various APIs when a program's binary format does not match the expected format for loading or execution.

Usage Context

This error can occur in several contexts, such as:

  • Attempting to load an executable file that has been corrupted or altered.
  • Using an API function incorrectly, leading to an attempt to load a file with an unsupported format.
  • Loading a file on a system where the required binary format is not supported.

Developer Interpretation

Developers should interpret this error as indicating a mismatch between the expected and actual binary format of a program. This can be due to various reasons, such as incorrect file type, corrupted data, or attempting to load a file in an unsupported context.

Related Errors

  • ERROR_INVALID_EXE_FORMAT (0x142) - Indicates that the executable file is not valid and cannot be loaded.
  • ERROR_BAD_EXE_FORMAT (0x143) - Similar to ERROR_BAD_FORMAT, but more specific to executable files.
  • ERROR_NOT_SAME_DEVICE (0x59) - Occurs when a file or directory is being moved between different drives, which can sometimes lead to format issues.

FAQ

Q: What does ERROR_BAD_FORMAT mean?

A: It indicates that the program's binary format is incorrect and cannot be loaded.

Q: How can I resolve this error?

A: Ensure that the file being loaded has the correct format and is not corrupted. Verify the context in which the file is being loaded to ensure compatibility with the system.

Summary

ERROR_BAD_FORMAT is a generic error code used by Windows APIs when an attempt is made to load a program with an incorrect binary format. Developers should handle this error by validating input files and ensuring that they are compatible with the target environment.