ERROR_DS_CLASS_MUST_BE_CONCRETE - 8359 (0x20A7)
The class of the object must be structural; you cannot instantiate an abstract class.
Updated: Feb 21, 2026
Technical Meaning
The error code ERROR_DS_CLASS_MUST_BE_CONCRETE indicates that an attempt was made to instantiate or reference a class in the directory service schema that is defined as abstract. In Windows, this typically pertains to Active Directory and its object classes.
Error Details
This error occurs when a developer or system attempts to create an instance of an abstract class within the context of Active Directory. Abstract classes are intended to serve as base classes for other derived classes but cannot be instantiated directly. The specific scenario where this error might arise includes operations involving object creation, modification, or deletion in the directory service.
Usage Context
This error is relevant primarily in scenarios involving Active Directory schema management and object manipulation through programming interfaces such as LDAP (Lightweight Directory Access Protocol) or other AD-related APIs provided by Windows. Developers working with these APIs must ensure that they are using concrete classes, which are fully defined and can be instantiated.
Developer Interpretation
Developers should understand that this error signifies a violation of the schema rules enforced by Active Directory. When encountering this error, it is necessary to review the class definitions in use and ensure that only concrete classes are being utilized for object creation or modification operations. This includes verifying that any custom schema extensions adhere to the requirement of having at least one concrete subclass.
Related Errors
ERROR_DS_OBJECT_CLASS_EXISTS(1932)ERROR_DS_CANT_MOD_OBJCLASS(8406)ERROR_DS_SCHEMA_NOT_LOADED(8576)
These errors may also be encountered in the context of Active Directory schema management and object class manipulation.
FAQ
Q: What does this error mean?
A: This error indicates that an attempt was made to instantiate or reference a class defined as abstract within the directory service schema. Abstract classes cannot be directly instantiated.
Q: How can I resolve this issue?
A: Ensure that you are using only concrete classes when performing operations such as object creation, modification, or deletion in Active Directory.
Summary
The error ERROR_DS_CLASS_MUST_BE_CONCRETE is a specific technical error related to the directory service schema in Windows. It occurs when an attempt is made to instantiate or reference an abstract class, which is not allowed. Developers must ensure that they are working with concrete classes and adhere to the schema rules enforced by Active Directory.