ERROR_SXS_DUPLICATE_DLL_NAME - 14021 (0x36C5)
Two or more components referenced directly or indirectly by the application manifest have files by the same name.
Updated: Feb 21, 2026
Technical Meaning
The ERROR_SXS_DUPLICATE_DLL_NAME error code indicates that the application manifest references two or more components with files having the same name. This can occur during the execution of an application, particularly when using the Side-by-Side assembly loader (SxS) to manage multiple versions of the same DLL.
Error Details
This error is typically encountered in scenarios where there are conflicting file names within the manifest or within the dependencies of those manifests. The SxS loader uses these manifests to determine which version of a DLL should be loaded, and encountering duplicate names can lead to ambiguity and potential issues during runtime.
Usage Context
The ERROR_SXS_DUPLICATE_DLL_NAME error is relevant in environments where applications are configured with multiple versions of the same DLL or where there are complex dependency chains within manifests. This error can also occur when deploying applications that rely on SxS for versioning and isolation.
Developer Interpretation
Developers should ensure that all components referenced by an application manifest have unique file names to avoid this error. When developing or modifying manifests, it is crucial to verify the uniqueness of file names within the manifest and its dependencies. This can be achieved through careful design and validation processes during development.
Related Errors
ERROR_SXS_FILE_HASH_MISMATCH(14023): Indicates a mismatch in file hashes.ERROR_SXS_MANIFEST_PARSE_FAILURE(14059): Occurs when the manifest cannot be parsed correctly.
FAQ
Q: What causes this error?
A: This error is caused by having two or more components with files that have the same name in an application manifest. Ensure all file names are unique within the manifest and its dependencies.
Q: How can I resolve this issue?
A: Review and modify the manifests to ensure that all referenced DLLs have unique names. Validate the manifests for correctness before deployment.
Summary
The ERROR_SXS_DUPLICATE_DLL_NAME error is a specific technical issue related to manifest file naming conflicts in Windows applications using SxS. Ensuring unique file names within manifests can prevent this error and maintain application integrity during execution.