What does Windows error code 8389 (ERROR_DS_AUX_CLS_TEST_FAIL) mean?

ERROR_DS_AUX_CLS_TEST_FAIL

The proposed auxiliary class relationship is invalid

Active Directory validates auxiliaryClass and systemAuxiliaryClass references on a classSchema object. The referenced class must exist, be active, and have a category that is valid for use as an auxiliary class under the MS-ADTS consistency rules. A structural class cannot simply be inserted into the auxiliary list to borrow its attributes.

Inspect the referenced classSchema object and its objectClassCategory. If a custom class was intended to augment another class, its schema definition must be designed as auxiliary before dependent classes reference it. Changing the relationship only in the consuming class does not convert the referenced class category.

What to inspect

• Resolve each auxiliary-class reference and read its objectClassCategory.
• Confirm the referenced class is active and imported before the dependent class.
• Do not use a structural class as a shortcut for adding optional attributes.

References

• MS-ADTS: schema consistency checks
• Microsoft: classSchema class
• IETF RFC 4512: LDAP directory models and schema