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Active Directory replication errors, such as error 8333: Directory object not found (ERROR_DS_OBJ_NOT_FOUND), indicate that the replication process is trying to find an object that does not exist or cannot be located in the directory. This could be due to various reasons, such as a missing or improperly deleted object, issues with replication metadata, or inconsistencies within the Active Directory. Below is a comprehensive troubleshooting guide to help you resolve this issue.

Steps to Troubleshoot and Fix Error 8333

1. Identify the Affected Object

The first step is to identify which object is causing the error. You can use the Event Viewer to find detailed information about the error.

  • Open the Event Viewer on the affected domain controller:
    • Go to Windows Logs > Directory Service.
    • Look for any error messages around the time the replication failed.

The event log entries may contain information about which object could not be found.

2. Run repadmin to Gather More Information

Use the repadmin tool to check the replication status and identify any errors:

repadmin /replsummary

This command will give you a summary of replication status across your domain controllers. If there are failures, it will also show you which DCs are involved.

You can also use:

repadmin /showrepl <DC_Name>

This command displays detailed replication status for a specific domain controller. Look for any references to missing objects or other errors.

3. Check for Deleted Objects

If the missing object was recently deleted, it might still exist in the Deleted Objects container, provided the Active Directory Recycle Bin feature is enabled.

  1. Enable the Recycle Bin (if not already enabled):
    Get-ADOptionalFeature -Filter {name -like "Recycle Bin"} | Enable-ADOptionalFeature -Identity "Recycle Bin Feature" -Scope ForestOrConfigurationSet -Target <YourForest>
    
  2. Use PowerShell to Check for Deleted Objects: You can search for deleted objects with PowerShell:

    Get-ADObject -Filter {isDeleted -eq $true} -IncludeDeletedObjects
    
  3. If you find the missing object, you can restore it using:

    Restore-ADObject -Identity <ObjectGUID>
    

4. Verify and Repair Replication Metadata

If the object has been deleted improperly, there might be lingering references in the replication metadata. You can clean up these references using ntdsutil:

  1. Open an elevated command prompt and run ntdsutil:
    ntdsutil
    
  2. Enter the following commands:
    metadata cleanup
    
  3. Follow the prompts to select the appropriate DC and remove any lingering objects.

5. Force Replication

After addressing the object issues, attempt to force replication:

repadmin /syncall /AdeP
  • The /A flag indicates all domain controllers, /d for verbose output, /e to include the entire forest, and /P to synchronize with partners even if there are lingering objects.

6. Check DNS Configuration

Make sure that the DNS configuration is correct and that all domain controllers can resolve each other’s names properly.

  • Use the following commands to check DNS resolution:
    nslookup <DC_Name>
    nslookup <DC_IP>
    
  • If there are issues, ensure that all DCs are configured to use the correct DNS servers.

Check the Event Viewer for other related errors, particularly in the Directory Service and DNS Server logs. Look for any warnings or errors that might be affecting replication.

8. Check for Network Issues

Ensure there are no network issues that could be impacting replication. This includes checking firewall settings and ensuring that ports required for Active Directory replication (like 135, 389, 636, 3268, and 3269) are open.

9. Check for Schema Issues

If there have been recent schema changes, make sure that they have replicated correctly across all domain controllers. You can use the schema.msc tool to verify the schema.

10. Last Resort: Seize FSMO Roles

If a domain controller is offline and cannot be brought back, and it holds FSMO roles, you may need to seize the roles to another DC. This should be done carefully to avoid inconsistencies.

  1. Use ntdsutil to seize FSMO roles:
    ntdsutil
    roles
    connections
    connect to server <new_fsmoserver>
    quit
    seize <role_name>
    
  2. Roles include: Schema Master, Domain Naming Master, PDC Emulator, RID Master, and Infrastructure Master.

Conclusion

Active Directory replication errors like error 8333 can be challenging, but following these steps should help you identify and fix the underlying issues. Always ensure you have proper backups before making changes to Active Directory objects or performing metadata cleanup. If issues persist, consider reaching out to Microsoft Support or consulting with experienced IT professionals.

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