When attempting to upgrade the schema using the VAS Schema Wizard or the ldifde command you receive the error "Command returned failure code: 8206"
1. Ensure you are logged on with a user who has Schema Admin, Enterprise Admin and Local Admin rights.
2. On Windows 2000 ensure the schema has write access enabled.
Refer to Microsoft KB Article ID 285172 - "Schema Updates Require Write Access to Schema in Active Directory"
3. Check that no domain controllers have been incorrectly removed from Active Directory using tools such as dcdiag.
Refer to Microsoft KB Article ID 216498 - "How to remove data in Active Directory after an unsuccessful domain controller demotion"