ERROR_DS_KEY_NOT_UNIQUE - 8527 (0x214F)
The object requested was not found, but an object with that key was found.
Updated: Feb 21, 2026
Technical Meaning
The error code ERROR_DS_KEY_NOT_UNIQUE indicates that a search operation was performed for an object using a key, but the object with the specified key could not be found. However, another object with the same key exists in the directory service.
Error Details
This error typically occurs when performing operations such as adding or modifying objects in Active Directory (AD) or other directory services where unique keys are used to identify objects. The presence of multiple objects with the same key can lead to ambiguity and operational issues, hence this specific error code is returned.
Usage Context
The context in which this error occurs depends on the operation being performed. For example, when attempting to add a new object that already has an existing key, or when modifying an object where another entry with the same key exists but is not the one intended for modification.
Developer Interpretation
Developers should interpret this error as indicating a potential issue with the uniqueness of keys in their directory service operations. It suggests that either there was a mistake in identifying the correct object or that the system encountered an unexpected state where multiple objects share the same key, which is not allowed by design.
Related Errors
ERROR_DS_NAME_NOT_UNIQUE(1572): Indicates that a name conflict exists within the directory service.ERROR_DS_OBJECT_ALREADY_EXISTS(8046): Suggests that an object with the specified attributes already exists, which might be related to the key issue but not exactly the same scenario.
FAQ
Q: What does ERROR_DS_KEY_NOT_UNIQUE mean?
A: It means a search operation found another object with the same key as intended, but no exact match was found for the requested object.
Q: How can I resolve this error?
A: Ensure that keys used in directory service operations are unique. Verify the object types and keys before performing operations to avoid such errors.
Summary
ERROR_DS_KEY_NOT_UNIQUE is a specific error code indicating issues with key uniqueness in directory services. Developers should ensure that their operations adhere to the requirement of unique keys to prevent this error from occurring.