ERROR_MUI_INVALID_LOCALE_NAME - 15103 (0x3AFF)
The RC Manifest has invalid culture name.
Updated: Feb 21, 2026
Technical Meaning
The error code ERROR_MUI_INVALID_LOCALE_NAME indicates that the resource manifest in a Windows application or component contains an invalid culture name. This can occur during localization and internationalization processes where the specified locale is not recognized by the system.
Error Details
This error typically arises when the RC (Resource Compiler) manifest used to compile localized resources includes a culture name that does not match any valid culture names defined in the Windows operating system. The culture name must adhere to specific naming conventions and be one of the supported cultures listed in the Windows locale database.
Usage Context
This error is relevant when dealing with multilingual applications or components that require localization support. It can occur during application startup, resource loading, or any operation involving localized resources.
Developer Interpretation
Developers should ensure that all culture names used in RC manifests are valid and correctly formatted according to the Windows locale database. Validating the culture name against a list of supported cultures is recommended to avoid this error.
Related Errors
ERROR_MUI_FILE_NOT_FOUND(15102, 0x3AF6): Indicates that a required resource file for localization was not found.ERROR_MUI_INVALID_SYNTAX(15104, 0x3B00): Suggests that the syntax used in the RC manifest is incorrect but does not specify an invalid culture name.
FAQ
Q: What causes this error?
A: The error occurs when the culture name specified in the RC manifest is invalid or unsupported by the Windows operating system.
Q: How can I resolve this issue?
A: Verify that all culture names used in your RC manifests are valid and correctly formatted. Use a list of supported cultures to ensure accuracy.
Summary
ERROR_MUI_INVALID_LOCALE_NAME is an error code indicating the presence of an invalid culture name in the resource manifest of a Windows application or component. Developers should validate culture names against the Windows locale database to prevent this issue.