How to Put Exchange Server in Maintenance Mode Using PowerShell

Before putting your Exchange server into maintenance mode, check the current component states and ensure you have the proper permissions and environment setup.

Open Exchange Management Shell as an administrator and run the following command to check the current server component states:

Get-ServerComponentState -Identity ExchangeServer01

This command displays all components and their current states. You should see components like HubTransport, ServerWideOffline, and others in 'Active' state before maintenance.

Next, verify your Exchange server version and role:

Get-ExchangeServer -Identity ExchangeServer01 | Select-Object Name, AdminDisplayVersion, ServerRole

If you're working with a Database Availability Group (DAG), check the DAG status:

Get-DatabaseAvailabilityGroup | Get-MailboxServer | Where-Object {$_.Name -eq "ExchangeServer01"}

The first step in maintenance mode is to drain the HubTransport component, which stops the server from accepting new messages while allowing existing messages to be processed.

Execute the following command to set HubTransport to draining state:

Set-ServerComponentState -Identity ExchangeServer01 -Component HubTransport -State Draining -Requester Maintenance

This command tells Exchange to stop accepting new messages but continue processing existing ones in the queue. The -Requester Maintenance parameter identifies why the component state was changed.

Monitor the transport queues to see the draining process:

Get-Queue -Server ExchangeServer01

Wait for the queues to drain naturally, or if you need to expedite the process, restart the transport services:

Restart-Service MSExchangeTransport
Restart-Service MSExchangeFrontEndTransport

After draining the HubTransport component, redirect any remaining messages in the queues to another Exchange server to ensure mail flow continues.

Identify a target server that can handle the redirected messages:

Get-ExchangeServer | Where-Object {$_.ServerRole -match "Mailbox" -and $_.Name -ne "ExchangeServer01"}

Redirect all messages from your maintenance server to the target server:

Redirect-Message -Server ExchangeServer01 -Target ExchangeServer02

This command moves all queued messages from ExchangeServer01 to ExchangeServer02. The process may take several minutes depending on the queue size.

Monitor the redirection progress:

Get-Queue -Server ExchangeServer01 | Where-Object {$_.MessageCount -gt 0}

You can also check specific queue details:

Get-Queue -Server ExchangeServer01 | Select-Object Identity, DeliveryType, Status, MessageCount, NextHopDomain

If your Exchange server is part of a DAG, you need to suspend the cluster node and move active database copies to other DAG members before proceeding with maintenance.

First, suspend the cluster node to prevent it from participating in cluster operations:

Suspend-ClusterNode -Name ExchangeServer01

Next, move all active database copies away from the maintenance server and block automatic activation:

Set-MailboxServer -Identity ExchangeServer01 -DatabaseCopyActivationDisabledAndMoveNow $True

Block automatic database activation on this server:

Set-MailboxServer -Identity ExchangeServer01 -DatabaseCopyAutoActivationPolicy Blocked

Verify that all active databases have been moved away from the maintenance server:

Get-MailboxDatabase | Get-MailboxDatabaseCopyStatus | Where-Object {$_.MailboxServer -eq "ExchangeServer01" -and $_.Status -eq "Mounted"}

Check the overall DAG health after moving databases:

Get-MailboxDatabaseCopyStatus | Where-Object {$_.MailboxServer -ne "ExchangeServer01"} | Sort-Object DatabaseName

The final step in enabling maintenance mode is setting the ServerWideOffline component to Inactive, which effectively takes the server out of service for all Exchange operations.

Execute the following command to set the server offline:

Set-ServerComponentState -Identity ExchangeServer01 -Component ServerWideOffline -State Inactive -Requester Maintenance

This command sets the server to offline state, preventing it from handling any Exchange services including client connections, mail flow, and database operations.

Verify the server is now in maintenance mode by checking all component states:

Get-ServerComponentState -Identity ExchangeServer01

You should see ServerWideOffline as 'Inactive' and HubTransport as 'Draining'. Other components may show various states depending on your Exchange version.

For a comprehensive health check, you can use the Exchange Health Checker script:

# Download and run HealthChecker.ps1 from Microsoft GitHub
.\HealthChecker.ps1 -Server ExchangeServer01 -OutputFilePath C:\Temp\

With your Exchange server now safely in maintenance mode, you can perform your planned maintenance tasks such as installing Cumulative Updates, applying security patches, or performing hardware maintenance.

During maintenance, monitor the other Exchange servers to ensure they're handling the additional load properly:

# Check queue status on other servers
Get-ExchangeServer | Where-Object {$_.ServerRole -match "Mailbox" -and $_.Name -ne "ExchangeServer01"} | ForEach-Object {
    Write-Host "Checking queues on $($_.Name)"
    Get-Queue -Server $_.Name | Where-Object {$_.MessageCount -gt 10}
}

Monitor database status on remaining DAG members:

Get-MailboxDatabaseCopyStatus | Where-Object {$_.MailboxServer -ne "ExchangeServer01"} | Sort-Object DatabaseName | Format-Table DatabaseName, MailboxServer, Status, CopyQueueLength, ReplayQueueLength

If you're installing Exchange Cumulative Updates, the typical process involves:

REM Run the CU installer from elevated command prompt
ExchangeServer2019-KB5000871-x64-en.exe /mode:upgrade /IAcceptExchangeServerLicenseTerms

After completing maintenance tasks, verify that Exchange services are running properly:

Get-Service | Where-Object {$_.Name -like "*Exchange*" -and $_.Status -ne "Running"}

After completing your maintenance tasks, you need to reverse the maintenance mode process in the correct order to safely bring your Exchange server back online.

Start by setting the ServerWideOffline component back to Active:

Set-ServerComponentState -Identity ExchangeServer01 -Component ServerWideOffline -State Active -Requester Maintenance

If your server is part of a DAG, resume the cluster node:

Resume-ClusterNode -Name ExchangeServer01

Unblock database activation and allow automatic activation:

Set-MailboxServer -Identity ExchangeServer01 -DatabaseCopyActivationDisabledAndMoveNow $False
Set-MailboxServer -Identity ExchangeServer01 -DatabaseCopyAutoActivationPolicy Unrestricted

Reactivate the HubTransport component:

Set-ServerComponentState -Identity ExchangeServer01 -Component HubTransport -State Active -Requester Maintenance

Restart the transport services to ensure proper mail flow:

Restart-Service MSExchangeTransport
Restart-Service MSExchangeFrontEndTransport

Verify all components are back to Active state:

Get-ServerComponentState -Identity ExchangeServer01

The final step is to thoroughly test that your Exchange server is fully operational and handling client connections and mail flow properly.

Test mail flow by sending a test message through the server:

# Test internal mail flow
$TestMailbox = "testuser@contoso.com"
Send-MailMessage -From "admin@contoso.com" -To $TestMailbox -Subject "Post-Maintenance Test" -Body "Testing mail flow after maintenance" -SmtpServer ExchangeServer01

Check that databases are mounting properly and accepting connections:

Get-MailboxDatabase | Where-Object {$_.Server -eq "ExchangeServer01"} | Get-MailboxDatabaseCopyStatus

Verify client connectivity by testing various protocols:

# Test connectivity to various Exchange services
Test-OutlookConnectivity -ProbeIdentity "OutlookMapiHttp.Protocol" -TargetResource ExchangeServer01
Test-WebServicesConnectivity -MailboxCredential (Get-Credential) -TrustAnySSLCertificate

Monitor transport queues to ensure normal mail flow:

Get-Queue -Server ExchangeServer01 | Where-Object {$_.MessageCount -gt 0} | Format-Table Identity, Status, MessageCount, NextHopDomain

Run a final health check using the Exchange Health Checker script:

.\HealthChecker.ps1 -Server ExchangeServer01 -OutputFilePath C:\Temp\PostMaintenance\

Compare the post-maintenance health report with your pre-maintenance baseline to identify any issues.