{"id":93429,"date":"2022-01-14T06:19:42","date_gmt":"2022-01-14T06:19:42","guid":{"rendered":"https:\/\/www.stellarinfo.com\/blog\/?p=93429"},"modified":"2025-07-21T10:23:54","modified_gmt":"2025-07-21T10:23:54","slug":"fix-exchange-dag-witness-server-failed-state","status":"publish","type":"post","link":"https:\/\/www.stellarinfo.com\/blog\/fix-exchange-dag-witness-server-failed-state\/","title":{"rendered":"How to Fix Exchange DAG Witness Failed State"},"content":{"rendered":"

Microsoft Exchange Database Availability Group or DAG<\/a> requires a witness server and witness directory (automatically created by the Exchange on the Witness Server) for maintaining quorum.<\/p>

A witness server or file witness server (FSW) provides automatic failover protection. It identifies which member server holds the mirror copy and which server holds the principal copy of the database, ensuring at least one server is active at any given time.<\/p>

But sometimes, due to underlying issues or misconfiguration in the Exchange DAG witness server may lead to a failed state, resulting in an unhealthy and compromised DAG. A witness server state may also show as failed if the server doesn’t boot due to hardware or software failure.<\/p>

To check the witness server status in DAG, use Get-DatabaseAvailabilityGroup<\/strong> cmdlet in Exchange Management Shell (EMS),<\/p>

Get-DatabaseAvailabilityGroup -Identity \"DAG01\" -Status | ft Name, Witness*, Servers<\/code><\/pre>
If the witness server has failed, the following error\/warning message is displayed in the output,<\/p>
WARNING: Database availability group 'DAG01' witness is in a failed state. The database availability group requires the witness server to maintain quorum. Please use the Set-DatabaseAvailabilityGroup cmdlet to re-create the witness server and the directory.\nWitnessServer : fsw.domain.local\nWitnessDirectory : C:\\DAGFileShareWitnesses\\DAG1.domain.local\nAlternateWitnessServer :\nAlternateWitnessDirectory :\nWitnessShareInUse : InvalidConfiguration\nDxStoreWitnessServers :<\/em><\/pre>
In this blog, you will learn a simple solution to fix the failed witness server state and bring your DAG back to a healthy state.<\/p>
Methods to Resolve DAG Witness Server Failed State in Exchange<\/strong><\/h2>
When the witness server fails due to any hardware or software issue rather than a network-related problem, set up a new witness server and then change the witness server and witness directory in the DAG using the Set-DatabaseAvailabilityGroup cmdlet<\/a>. The command is as follow,<\/p>
Set-DatabaseAvailabilityGroup -Identity \"DAGName\" -WitnessServer \"NewFileWitnessServerName” -WitnessDirectory NonRootLocalLongFullPath<\/code><\/pre>
For instance,<\/p>
Set-DatabaseAvailabilityGroup -Identity \"DAG01\" -WitnessServer \"FSW02.abc.com\" -WitnessDirectory C:\\DAG01<\/code><\/pre>
If the Windows firewall is enabled, you may get the following warning message in the output,<\/p>
WARNING: Unable to access file shares on witness server 'FSW02.abc.com'. The database availability group may be more vulnerable to failures until this problem is corrected. You can use the Set-DatabaseAvailabilityGroup cmdlet to try the operation again. Error: The network path was not found Unable to change the quorum for database availability group DAG01. The network path for witness server '\\\\FSW02.abc.com\\DAG01.abc.com' was not found. This may be due to firewall settings.<\/em><\/pre>
In such a case, you may either disable the Windows Firewall or add an exception for File and Printer Sharing <\/strong>on SMB port 445 <\/strong>(used by the witness server). Then execute the cmdlet.<\/p>
To verify the new DAG witness server, execute the following cmdlet,<\/p>
Get-DatabaseAvailabilityGroup -Identity \"DAG01\" -Status | ft Name, Witness*, Servers<\/code><\/pre>
If the output displays the new Witness server and witness directory, you have successfully changed the witness server.<\/p>
You may also perform these steps via Exchange Admin Center (EAC). The steps are as follow,<\/p>