Troubleshooting DFSR SYSVOL Replication Failures on Windows Server: Migration and Recovery
Distributed File System Replication (DFSR) is a critical component for maintaining consistency across domain controllers, particularly for the System Volume (SYSVOL) share. When DFSR SYSVOL experiences failures, whether during migration from File Replication Service (FRS) or in an already-migrated environment, it can severely impact Group Policy application and overall domain functionality. This article delves into common scenarios where DFSR SYSVOL fails to migrate, replicate, or share, providing a comprehensive solution to these challenging issues.
Understanding SYSVOL Replication and DFSR¶
SYSVOL is a shared directory that stores important domain information, including Group Policy Objects (GPOs) and logon scripts. Its proper replication across all domain controllers is paramount for a healthy Active Directory environment. DFSR replaced FRS as the preferred replication engine for SYSVOL in Windows Server 2008 and later, offering improved performance and reliability.
Migration from FRS to DFSR is a multi-step process, and any interruption can lead to inconsistencies. Similarly, in an existing DFSR environment, new domain controllers must correctly integrate and replicate SYSVOL to function properly. When these processes falter, administrators face significant challenges in managing their domain infrastructure.
Symptoms of DFSR SYSVOL Replication Failures¶
Troubleshooting DFSR SYSVOL issues often begins with recognizing specific symptoms. These failures typically manifest in two primary scenarios, each with distinct indicators in event logs and diagnostic output. Understanding these symptoms is the first step toward effective resolution.
Scenario 1: SYSVOL Migration Stuck in ‘Preparing’ State¶
During the migration from FRS to DFSR, domain controllers should progress through several states: Start, Prepared, Redirected, and Eliminated. A common issue is when no domain controllers advance beyond the ‘Preparing’ phase, even after verifying Active Directory (AD) replication convergence. This persistence can occur even within the same AD site as the Primary Domain Controller Emulator (PDCE), where AD replication is typically rapid, and after explicitly running DFSRDIAG.EXE POLLAD.
The DFSRMIG.EXE /GETMIGRATIONSTATE command will prominently display this stalled state:
DFSRMIG.EXE /GETMIGRATIONSTATE
Domain Controller (Local Migration State) - DC Type
===================================================
2008R2-MIG-01 ('Preparing') - Primary DC
2008R2-MIG-02 ('Preparing') - Writable DC
Migration has not yet reached a consistent state on all Domain Controllers.
State information might be stale due to AD latency.
Further examination of the DFS Replication event log on the PDCE typically reveals an Event ID: 8028, indicating an Error: 5 (Access is denied.). This error suggests a permission-related problem preventing DFSR from transitioning to the ‘PREPARED’ state. The associated DFSR Debug log provides more granular detail, explicitly showing “Insufficient Rights” errors during attempts to modify Active Directory attributes related to DFSR local settings.
Log Name: DFS Replication
Source: DFSR
Date: <DateTime>
Event ID: 8028
Task Category: None
Level: Error
Keywords: Classic
User: N/A
Computer: 2008r2-mig-01.cohowinery.com
Description:
DFSR Migration was unable to transition to the 'PREPARED' state for Domain Controller 2008R2-MIG-01. DFSR will retry the next time it polls the Active Directory. To force an immediate retry, execute the command 'dfsrdiag /pollad'.
Additional Information:
Domain Controller: 2008R2-MIG-01
Error: 5 (Access is denied.)
The debug log further pinpoints the issue:
<DateTime> 1524 CFAD 2570 [ERROR] Config::AdAttrEditor::ModifyValue Failed to ldap_modify_s(). dn:cn=DFSR-LocalSettings,CN=2008R2-MIG-01,OU=Domain Controllers,DC=cohowinery,DC=com Error:Insufficient Rights
<DateTime> 1524 SYSM 586 [ERROR] Migration::SysvolMigrationTask::Step [MIG] Failed Migration task.Error:
+ [Error:5(0x5) Migration::SysVolMigration::Migrate migrationserver.cpp:1200 1524 W Access is denied.]
...
+ [Error:50(0x32) Config::AdAttrEditor::ModifyValue ad.cpp:2578 1524 U Insufficient Rights]
Scenario 2: New Domain Controller Fails SYSVOL Replication¶
In environments where SYSVOL already replicates using DFSR, promoting a new domain controller (DC) should result in it successfully replicating SYSVOL and creating the necessary SYSVOL and NETLOGON shares. However, this scenario describes a failure where the new DC does not achieve this, leaving the critical shares uncreated and replication stalled. This prevents the new DC from fully functioning as a domain controller and applying Group Policies.
The DFS Replication event log on the new, affected DC will typically show an Event ID: 6016, again indicating an Error: 5 (Access is denied.). This error specifically points to DFSR’s inability to update its configuration in Active Directory Domain Services, hinting at a permissions problem that prevents the new DC from integrating correctly into the DFSR replication topology. The accompanying DFSR Debug log confirms these “Insufficient Rights” during attempts to create or modify SYSVOL-related objects in Active Directory.
Log Name: DFS Replication
Source: DFSR
Date: <DateTime>
Event ID: 6016
Task Category: None
Level: Warning
Keywords: Classic
User: N/A
Computer: 2008-R2-TSPDC2.tailspintoys.com
Description:
The DFS Replication service failed to update configuration in Active Directory Domain Services. The service will retry this operation periodically.
Additional Information:
Object Category: msDFSR-LocalSettings
Object DN: CN=DFSR-LocalSettings,CN=2008-R2-TSPDC2,OU=Domain Controllers,DC=tailspintoys,DC=com**
Error: 5 (Access is denied.)
Domain Controller: 2008-R2-TSPDC1.tailspintoys.com
Polling Cycle: 60
The debug log on the new DC clarifies the permission issue:
<DateTime> 1712 CFAD 2570 [ERROR] Config::AdAttrEditor::ModifyValue Failed to ldap_modify_s(). dn:cn=DFSR-LocalSettings,CN=2008-R2-TSPDC2,OU=Domain Controllers,DC=tailspintoys,DC=com Error:Insufficient Rights
<DateTime> 1712 CFAD 11508 [ERROR] Config::AdReader::Read [SYSVOL] (Ignored) Failed to create SysVol objects, Error:
...
+ [Error:50(0x32) Config::AdAttrEditor::ModifyValue ad.cpp:2578 1712 U Insufficient Rights]
Furthermore, the DFSR debug log on the PDCE might show errors like Event:1168(0x490) Element not found, indicating that the PDCE cannot properly build the replication topology for the new DC due to missing configuration elements, a direct consequence of the permission issues encountered by the new DC itself.
<DateTime> 1792 CFAD 6160 [ERROR] Config::AdSnapshot::BuildPartnersSubTree Failed to create computer tree for partner:CN=2008-R2-TSPDC2,CN=Topology,CN=Domain System Volume,CN=DFSR-GlobalSettings,CN=System,DC=tailspintoys,DC=com, Error:
+ [Error:1168(0x490) Config::AdSnapshot::BuildPartnerComputerSubTree ad.cpp:6018 1792 W Element not found.]
...
The Root Cause: Missing User Rights Assignment¶
The underlying cause for both scenarios, as indicated by the “Access is denied” and “Insufficient Rights” errors, stems from a misconfiguration of user rights assignments within the domain. Specifically, the default user rights assignment “Manage Auditing and Security Log” (SeSecurityPrivilege) has been inadvertently removed from the built-in Administrators group. This particular user right is crucial for certain operations that DFSR performs, especially when creating and modifying Active Directory objects related to SYSVOL replication.
The removal of this user right from Administrators on domain controllers is explicitly unsupported by Microsoft and can lead to various system malfunctions, including the DFSR SYSVOL issues observed. DFSR migration, as well as the initial setup of DFSR replication for a new DC, requires a user or a process running under the context of a user with membership in the built-in Administrators group in that domain. All domain controllers are automatically members of this built-in group and rely on its default privileges to operate correctly. Without the “Manage Auditing and Security Log” right, DFSR cannot make the necessary security descriptor changes to AD objects, leading to the observed replication failures.
Resolution Steps for DFSR SYSVOL Failures¶
Resolving these DFSR SYSVOL replication failures primarily involves restoring the “Manage Auditing and Security Log” user right to the built-in Administrators group. This is a critical security policy setting that, once corrected, allows DFSR to perform its required Active Directory modifications. The following steps must be followed precisely, using an elevated command prompt while logged on as a Domain Admin to ensure proper permissions.
General Steps to Correct User Rights Assignment¶
These initial steps are common to both scenarios and focus on identifying and correcting the Group Policy that has altered the “Manage Auditing and Security Log” user right.
-
Identify the Responsible Group Policy:
To determine which Group Policy Object (GPO) is overriding the default security setting on your domain controllers, run theGPRESULT.EXEcommand on the Primary Domain Controller Emulator (PDCE). This command generates an HTML report detailing all applied Group Policies.
GPRESULT.EXE /H secpol.htm
This command will create a file namedsecpol.htmin the current directory, which can be opened with any web browser. -
Review the Security Policy Report:
Open the generatedsecpol.htmfile in a web browser. Within the report, select “Show All” to expand all sections. Search for the entry “Manage Auditing and Security Log”. This section will clearly list the specific Group Policy that is applying this setting and, crucially, which groups or users are currently assigned or missing this right. -
Edit the Group Policy Object (GPO):
Once the offending GPO is identified (e.g., “Default Domain Controllers Policy” or a custom security policy), use the Group Policy Management Console (GPMC.MSC) to edit it. Navigate toComputer Configuration > Policies > Windows Settings > Security Settings > Local Policies > User Rights Assignment. Locate “Manage auditing and security log” and add the Administrators group to its assigned users. Ensure that the “Administrators” group is explicitly listed. -
Force Group Policy Update and AD/SYSVOL Convergence:
After modifying the GPO, it’s essential to ensure that this change propagates throughout Active Directory and is applied to all domain controllers. On the PDCE, execute the following command:
GPUPDATE /FORCE
Allow sufficient time for Active Directory and SYSVOL replication to converge across all domain controllers. This ensures that the updated Group Policy is received and processed by all DCs.
Scenario 1 Specific Resolution: Completing FRS to DFSR Migration¶
Once the “Manage Auditing and Security Log” user right is correctly assigned, follow these steps to proceed with or restart the SYSVOL migration process.
-
Update Security Token:
After forcing the Group Policy update, sign out from the PDCE and then log back on. This action is necessary to ensure that your user’s security token is refreshed with the newly assigned user right, allowing subsequent DFSR migration commands to execute with the correct permissions. -
Create Global Objects:
Execute the following command on the PDCE. This command is crucial for creating or updating global objects in Active Directory that DFSR uses for the migration process. It leverages the now-corrected permissions.
DFSRMIG.EXE /CREATEGLOBALOBJECTS
This step ensures the necessary AD objects for DFSR are properly created and configured. -
Allow Replication and Poll AD:
Allow Active Directory and SYSVOL replication to converge again on all domain controllers to propagate the changes made byDFSRMIG.EXE /CREATEGLOBALOBJECTS. On the PDCE, then run:
DFSRDIAG.EXE POLLAD DFSRMIG.EXE /GETMIGRATIONSTATE
DFSRDIAG.EXE POLLADforces DFSR services on all domain controllers to poll Active Directory for configuration changes.DFSRMIG.EXE /GETMIGRATIONSTATEallows you to monitor the progress of the migration. -
Validate Prepared State:
Continuously monitor the output ofDFSRMIG.EXE /GETMIGRATIONSTATE. You should now observe that some or all of the domain controllers transition to the ‘Prepared’ state. This indicates that the permission issue has been resolved, and the migration can now proceed normally through the remaining stages (Redirected, Eliminated). At this point, you can continue with the next phase of your SYSVOL migration as planned.
DFSR Migration States Table¶
To better understand the migration process, here’s a quick reference for the DFSR migration states:
| State ID | State Name | Description |
|---|---|---|
| 0 | Start | FRS is replicating SYSVOL. DFSR is not involved in SYSVOL. This is the initial state before migration begins. |
| 1 | Prepared | DFSR is replicating a copy of SYSVOL in a hidden folder (SYSVOL_DFSR). FRS is still actively replicating the primary SYSVOL. The DFSR replicated data is synchronized with FRS data, but not yet active. |
| 2 | Redirected | Clients on the domain controller are now using the DFSR-replicated SYSVOL. FRS is still replicating its SYSVOL, but clients no longer access it. This is typically the first visible change for clients. |
| 3 | Eliminated | FRS is no longer replicating SYSVOL. The FRS-managed SYSVOL is removed, and DFSR is solely responsible for SYSVOL replication. This is the final and desired state. |
| 4 | Backrolling | This state is entered during a rollback operation, moving back from a higher state to a lower one (e.g., from Redirected back to Prepared or Start). |
| 5 | Aborted | The migration process has failed or been explicitly stopped at an intermediate stage. This often requires manual intervention and cleanup. |
Scenario 2 Specific Resolution: New DC SYSVOL Replication¶
For a new domain controller failing to replicate SYSVOL in an existing DFSR environment, the resolution also starts with correcting the user rights assignment, followed by a service restart.
-
Identify and Edit Group Policy (as above):
Follow steps 1-3 from the “General Steps to Correct User Rights Assignment” section to identify the GPO and add the Administrators group to the “Manage Auditing and Security Log” user right. -
Force Group Policy Update on Affected DC:
Allow AD and SYSVOL replication to converge throughout the domain. On the affected new domain controller, execute the following command to ensure it receives the updated Group Policy:
GPUPDATE /FORCE -
Restart DFSR Service:
After the policy has been applied, restart the DFS Replication service on the affected domain controller. This will force DFSR to re-read its configuration from Active Directory, including the newly granted permissions, and attempt to initialize SYSVOL replication.
net stop dfsr net start dfsr -
Validate Shares and Replication:
After the service restarts, allow a few minutes for DFSR to initialize. Validate that the domain controller now correctly shares bothSYSVOLandNETLOGON. You can check this by runningnet sharefrom the command prompt. Also, verify that SYSVOL is replicating inbound by checking the DFS Replication event log for success events or by usingDFSRDIAGcommands.
Workaround: Manual SYSVOL Sharing (Temporary)¶
In situations where Group Policy cannot be applied because SYSVOL itself is not shared on any of the domain controllers (a chicken-and-egg problem), a temporary workaround involving manual SYSVOL sharing can be used to facilitate GPO editing. This should only be a short-term measure to fix the root cause.
-
Manually Share SYSVOL:
Edit the following registry value on a domain controller:
Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netlogon\parameters Value: SysvolReady Type: REG_DWORD Data: 1
After setting this value, runnet sharefrom an elevated command prompt to verify that theSYSVOLshare is now active. This trick makes Netlogon believe SYSVOL is ready for sharing. -
Open Policy and Add User Right:
Now thatSYSVOLis shared (even if temporarily), you should be able to access and edit Group Policy. OpenGPMC.MSC, identify the problematic GPO (as per general step 1), and add the Administrators group to the “Manage auditing and security log” user right. -
Force Group Policy Update:
Executegpupdate /forceto apply the corrected policy.Note: It is possible that a background process related to SYSVOL migration or DFSR might unshare SYSVOL again shortly after you manually share it, especially if the underlying problem (missing user right) isn’t fully resolved. You may need to repeat the manual sharing (
SysvolReady=1andnet share) between step 2 and step 3 to ensure thegpupdatecommand can succeed. -
Continue with Scenario Specific Steps:
Once the policy is applied and stable, proceed with the relevant resolution steps for Scenario 1 or Scenario 2 as outlined above. The manual sharing was merely to allow the policy fix to take effect.
Flowchart for DFSR SYSVOL Troubleshooting¶
To visualize the troubleshooting process, here’s a simplified flowchart using Mermaid syntax:
mermaid
graph TD
A[Start: DFSR SYSVOL Failure Detected] --> B{Symptoms: Migration Stuck or New DC Fails?};
B -- Migration Stuck ('Preparing') --> C[Scenario 1: Examine Event ID 8028 & DFSR Debug Logs];
B -- New DC Fails Replication/Shares --> D[Scenario 2: Examine Event ID 6016 & DFSR Debug Logs];
C --> E{Logs show "Access is denied." / "Insufficient Rights" for CN=DFSR-LocalSettings?};
D --> E;
E -- Yes --> F[Root Cause: "Manage Auditing and Security Log" (SeSecurityPrivilege) removed from Administrators Group];
E -- No --> G[Investigate other DFSR/AD replication issues];
F --> H{Is SYSVOL currently shared on any DC?};
H -- No (Can't access GPO) --> I[Workaround: Manually set SysvolReady=1 in Registry];
I --> J[Run net share to verify SYSVOL is shared];
J --> K[Edit GPO (GPMC.MSC): Add Administrators to "Manage Auditing and Security Log"];
H -- Yes --> K;
K --> L[Run GPUPDATE /FORCE on PDCE (and affected DC for Scenario 2)];
L --> M[Allow AD/SYSVOL Replication Convergence];
M --> N{Are you troubleshooting Scenario 1 (Migration)?};
N -- Yes --> O[Sign out/Log back in PDCE (for token refresh)];
O --> P[Run DFSRMIG.EXE /CREATEGLOBALOBJECTS];
P --> Q[Run DFSRDIAG.EXE POLLAD & DFSRMIG.EXE /GETMIGRATIONSTATE];
Q --> R{Are DCs now in 'Prepared' state?};
N -- No --> S[Restart DFSR Service on affected DC];
S --> T{Are SYSVOL/NETLOGON shares created and replicating inbound?};
R -- Yes --> U[Continue DFSR migration];
T -- Yes --> V[Issue Resolved];
U --> V;
R -- No --> G;
T -- No --> G;
Additional Important Considerations¶
It’s crucial to understand certain nuances about DFSR SYSVOL behavior to avoid common pitfalls.
-
DFSRMIG AD Updates vs. Registry Updates:
It is possible forDFSRMIGto successfully update Active Directory objects but fail to update the local registry on a domain controller. If the AD updates are completed successfully to create the SYSVOL replication group but the necessary registry changes for the DFSR service are not made due to missing user rights, you might only seeEvent ID 8010indicating that migration is underway, without seeing the actual state change. This highlights that “Access is denied” can manifest subtly across different operational layers. -
Normal vs. Abnormal ‘Preparing’ State Duration:
For domain controllers to remain in the ‘Preparing’ state for an extended period during a migration is normal, especially in large, geographically dispersed environments where Active Directory replication convergence may take hours or even days. However, it is not normal for DCs to remain stuck in this state after Active Directory replication has clearly reached those domain controllers and at least 15 minutes (the default DFSR AD polling interval) has passed. This scenario points to a blockage like the missing user right, not just replication latency. -
Avoiding Manual SYSVOL Sharing (Permanent Workaround):
Do not attempt to permanently work around DFSR SYSVOL issues by manually sharingSYSVOLandNETLOGONor by settingSYSVOLREADY=1in the registry without addressing the root cause. While these steps might temporarily make the shares appear, they can lead to a critical flaw where the domain controller contacts itself for Group Policy. Since the DC cannot populate itsSYSVOLcorrectly due to the underlying permission issue, any subsequent Group Policy changes designed to fix the user rights assignment will not be applied to that DC, perpetuating the problem and rendering the DC ineffective for GPO processing. -
Inter-site Change Notification:
For environments with multiple Active Directory sites, the time it takes for changes to replicate can significantly impact DFSR migration progress. Lowering the Active Directory replication convergence time, especially by utilizing Inter-site Change Notification, can accelerate the propagation of GPO changes and DFSR configuration updates. While beyond the scope of this article, understanding and optimizing AD replication is an important part of a healthy DFSR environment.
By diligently following these resolution steps and understanding the underlying mechanisms, administrators can effectively troubleshoot and resolve DFSR SYSVOL replication failures, ensuring the stability and functionality of their Windows Server domains.
Your Thoughts and Experiences¶
Have you encountered similar DFSR SYSVOL replication failures in your environment? What specific challenges did you face, and how did you resolve them? Share your insights and troubleshooting tips in the comments below to help the community.
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