Knowledge

ERROR_SXS_MANIFEST_INVALID_REQUIRED_DEFAULT_NAMESPACE - 14019 (0x36C3)

The manifest has a default namespace specified on the assembly element but its value is not "urn:schemas-microsoft-com:asm.v1".

Updated: Feb 21, 2026

Technical Background

The ERROR_SXS_MANIFEST_INVALID_REQUIRED_DEFAULT_NAMESPACE error code indicates a specific issue with the Side-by-Side (SXS) manifest files used in Windows. SXS manifests are XML documents that provide metadata about assemblies and their dependencies, enabling the runtime to manage assembly loading and versioning.

Error Details

This error occurs when an SXS manifest contains a default namespace on the assembly element, but its value is not set to urn:schemas-microsoft-com:asm.v1. This mismatch can lead to incorrect behavior or failure of the application that relies on this manifest for assembly resolution.

Common Causes

  • Incorrect Namespace Declaration: The assembly element in the SXS manifest has a default namespace with a value other than urn:schemas-microsoft-com:asm.v1. This is a critical requirement enforced by the Windows runtime to ensure correct interpretation of the manifest content.
  • Manifest Corruption or Modification: The manifest file may have been altered, leading to an invalid namespace declaration. This could occur due to accidental changes during manual editing or through automated processes that do not correctly preserve the required namespace.

Real-World Context

This error typically manifests when attempting to load a specific assembly using the SXS infrastructure. It can affect applications and services that rely on correct assembly resolution, potentially leading to runtime failures or unexpected behavior.

Is This Error Critical?

The criticality of this error depends on the application's reliance on the affected manifest. If the application is mission-critical and heavily dependent on the specific assembly being loaded correctly, then this error can be highly impactful. However, for less critical applications, it may only result in a warning or degraded functionality.

How to Diagnose

  1. Review Manifest File: Inspect the SXS manifest file to identify where the assembly element is declared and ensure its namespace matches urn:schemas-microsoft-com:asm.v1. Use tools like XML editors or validation utilities to check for any discrepancies.
  2. Validate Assembly Loading Context: Ensure that the context in which the assembly is being loaded complies with the requirements specified by the manifest. This includes verifying the runtime version and other dependencies.
  3. Check Application Configuration: Review application configuration files, such as app.config or web.config, to ensure they are correctly referencing the SXS manifests without any unintended modifications.

How to Resolve

  1. Correct Namespace Declaration: Modify the manifest file to set the default namespace of the assembly element to urn:schemas-microsoft-com:asm.v1. Ensure that no other elements in the manifest conflict with this requirement.
  2. Restore Data Integrity: If the manifest has been corrupted, restore a known good copy from backup or source control. Carefully validate any changes made during the restoration process.
  3. Retest Application: After making corrections to the manifest file, retest the application to ensure that it functions correctly and no longer encounters the ERROR_SXS_MANIFEST_INVALID_REQUIRED_DEFAULT_NAMESPACE error.

Developer Notes

Developers should be aware of the strict requirements for SXS manifests when working with assembly loading in Windows applications. Ensuring compliance with these standards can prevent runtime errors and improve application stability.

Related Errors

  • ERROR_SXS_FILE_HASH_MISMATCH: Occurs when there is a mismatch between the expected hash value and the actual hash value of an assembly file.
  • ERROR_SXS_MANIFEST_IDENTITY_NOT_VALID_FOR_PROCESS: Indicates that the manifest identity does not match the process requirements.
  • ERROR_SXS_MANIFEST_FORMAT_ERROR: General error related to issues with the format of SXS manifests.

FAQ

Q: What causes this error?

A: This error is caused by an incorrect namespace declaration in the assembly element of the SXS manifest, specifically when it does not match urn:schemas-microsoft-com:asm.v1. It can also occur due to corruption or modification of the manifest file.

Q: How do I fix this issue?

A: Correct the namespace declaration in the manifest file and ensure that no other elements conflict with this requirement. Validate the assembly loading context and retest the application after making these changes.

Summary

The ERROR_SXS_MANIFEST_INVALID_REQUIRED_DEFAULT_NAMESPACE error indicates a specific issue with SXS manifests, where the default namespace of the assembly element does not match the required value. This can lead to runtime failures in applications that rely on correct assembly resolution. By carefully reviewing and correcting the manifest file, developers can resolve this issue and ensure application stability.