Windows Virtual Desktop Agent

The Azure Virtual Desktop Agent can cause connection issues because of multiple factors:

• An error on the broker that makes the agent stop the service.
• Problems with updates.
• Issues with installing during the agent installation, which disrupts connection to the session host.

This article will guide you through solutions to these common scenarios and how to address connection issues.

[!NOTE] For troubleshooting issues related to session connectivity and the Azure Virtual Desktop agent, we recommend you review the event logs in Event Viewer > Windows Logs > Application. Look for events that have one of the following sources to identify your issue:

• WVD-Agent
• WVD-Agent-Updater
• RDAgentBootLoader
• MsiInstaller

Error: The RDAgentBootLoader and/or Remote Desktop Agent Loader has stopped running

If you're seeing any of the following issues, this means that the boot loader, which loads the agent, was unable to install the agent properly and the agent service isn't running:

• RDAgentBootLoader is either stopped or not running.
• There's no status for Remote Desktop Agent Loader.

To resolve this issue, start the RDAgent boot loader:

1. In the Services window, right-click Remote Desktop Agent Loader.
2. Select Start. If this option is greyed out for you, you don't have administrator permissions and will need to get them to start the service.
3. Wait 10 seconds, then right-click Remote Desktop Agent Loader.
4. Select Refresh.
5. If the service stops after you started and refreshed it, you may have a registration failure. For more information, see INVALID_REGISTRATION_TOKEN.

Error: INVALID_REGISTRATION_TOKEN

Go to Event Viewer > Windows Logs > Application. If you see an event with ID 3277, that says INVALID_REGISTRATION_TOKEN in the description, the registration token that you have isn't recognized as valid.

To resolve this issue, create a valid registration token:

1. To create a new registration token, follow the steps in the Generate a new registration key for the VM section.

2. Open the Registry Editor.

3. Go to HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > RDInfraAgent.

4. Select IsRegistered.

5. In the Value data: entry box, type 0 and select Ok.

6. Select RegistrationToken.

7. In the Value data: entry box, paste the registration token from step 1.

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8. Open a command prompt as an administrator.

9. Enter net stop RDAgentBootLoader.

10. Enter net start RDAgentBootLoader.

11. Open the Registry Editor.

12. Go to HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > RDInfraAgent.

13. Verify that IsRegistered is set to 1 and there is nothing in the data column for RegistrationToken.

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Error: Agent cannot connect to broker with INVALID_FORM

Go to Event Viewer > Windows Logs > Application. If you see an event with ID 3277 that says "INVALID_FORM" in the description, something went wrong with the communication between the agent and the broker. The agent can't connect to the broker or reach a particular URL because of certain firewall or DNS settings.

To resolve this issue, check that you can reach BrokerURI and BrokerURIGlobal:

1. Open the Registry Editor.

2. Go to HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > RDInfraAgent.

3. Make note of the values for BrokerURI and BrokerURIGlobal.

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4. Open a browser and go to api/health.

5. Open another tab in the browser and go to api/health.

6. If the network isn't blocking broker connection, both pages will load successfully and will show a message that says "RD Broker is Healthy" as shown in the following screenshots.

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7. If the network is blocking broker connection, the pages will not load, as shown in the following screenshot.

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8. If the network is blocking these URLs, you will need to unblock the required URLs. For more information, see Required URL List.

9. If this does not resolve your issue, make sure that you do not have any group policies with ciphers that block the agent to broker connection. Azure Virtual Desktop uses the same TLS 1.2 ciphers as Azure Front Door. For more information, see Connection Security.

Error: 3703

Go to Event Viewer > Windows Logs > Application. If you see an event with ID 3703 that says "RD Gateway Url: is not accessible" in the description, the agent is unable to reach the gateway URLs. To successfully connect to your session host and allow network traffic to these endpoints to bypass restrictions, you must unblock the URLs from the Required URL List. Also, make sure your firewall or proxy settings don't block these URLs. Unblocking these URLs is required to use Azure Virtual Desktop.

To resolve this issue, verify that your firewall and/or DNS settings are not blocking these URLs:

Error: 3019

Go to Event Viewer > Windows Logs > Application. If you see an event with ID 3019, this means the agent can't reach the web socket transport URLs. To successfully connect to your session host and allow network traffic to bypass these restrictions, you must unblock the URLs listed in the the Required URL list. Work with the Azure Networking team to make sure your firewall, proxy, and DNS settings aren't blocking these URLs. You can also check your network trace logs to identify where the Azure Virtual Desktop service is being blocked. If you open a support request for this particular issue, make sure to attach your network trace logs to the request.

Error: InstallationHealthCheckFailedException

Go to Event Viewer > Windows Logs > Application. If you see an event with ID 3277 that says "InstallationHealthCheckFailedException" in the description, that means the stack listener isn't working because the terminal server has toggled the registry key for the stack listener.

To resolve this issue:

Error: ENDPOINT_NOT_FOUND

Go to Event Viewer > Windows Logs > Application. If you see an event with ID 3277 that says "ENDPOINT_NOT_FOUND" in the description that means the broker couldn't find an endpoint to establish a connection with. This connection issue can happen for one of the following reasons:

• There aren't VMs in your host pool
• The VMs in your host pool aren't active
• All VMs in your host pool have exceeded the max session limit
• None of the VMs in your host pool have the agent service running on them

To resolve this issue:

Error: InstallMsiException

Go to Event Viewer > Windows Logs > Application. If you see an event with ID 3277, that says InstallMsiException in the description, the installer is already running for another application while you're trying to install the agent, or a policy is blocking the msiexec.exe program from running.

To resolve this issue, disable the following policy:

• Turn off Windows Installer
  • Category Path: Computer Configuration\Administrative Templates\Windows Components\Windows Installer

[!NOTE] This isn't a comprehensive list of policies, just the ones we're currently aware of.

To disable a policy:

1. Open a command prompt as an administrator.

2. Enter and run rsop.msc.

3. In the Resultant Set of Policy window that pops up, go to the category path.

4. Select the policy.

5. Select Disabled.

6. Select Apply.

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Error: Win32Exception

Go to Event Viewer > Windows Logs > Application. If you see an event with ID 3277, that says InstallMsiException in the description, a policy is blocking cmd.exe from launching. Blocking this program prevents you from running the console window, which is what you need to use to restart the service whenever the agent updates.

To resolve this issue, disable the following policy:

• Prevent access to the command prompt
  • Category Path: User Configuration\Administrative Templates\System

[!NOTE] This isn't a comprehensive list of policies, just the ones we're currently aware of.

To disable a policy:

1. Open a command prompt as an administrator.
2. Enter and run rsop.msc.
3. In the Resultant Set of Policy window that pops up, go to the category path.
4. Select the policy.
5. Select Disabled.
6. Select Apply.

Error: Stack listener isn't working on Windows 10 2004 VM

Run qwinsta in your command prompt and make note of the version number that appears next to rdp-sxs. If you're not seeing the rdp-tcp and rdp-sxs components say Listen next to them or they aren't showing up at all after running qwinsta, it means that there's a stack issue. Stack updates get installed along with agent updates, and when this installation goes awry, the Azure Virtual Desktop Listener won't work.

To resolve this issue:

1. Open the Registry Editor.

2. Go to HKEY_LOCAL_MACHINE > SYSTEM > CurrentControlSet > Control > Terminal Server > WinStations.

3. Under WinStations you may see several folders for different stack versions, select the folder that matches the version information you saw when running qwinsta in your Command Prompt.

4. Find fReverseConnectMode and make sure its data value is 1. Also make sure that fEnableWinStation is set to 1.

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5. If fReverseConnectMode isn't set to 1, select fReverseConnectMode and enter 1 in its value field.

6. If fEnableWinStation isn't set to 1, select fEnableWinStation and enter 1 into its value field.

7. Restart your VM.

[!NOTE] To change the fReverseConnectMode or fEnableWinStation mode for multiple VMs at a time, you can do one of the following two things:

• Export the registry key from the machine that you already have working and import it into all other machines that need this change.
• Create a group policy object [GPO] that sets the registry key value for the machines that need the change.

1. Go to HKEY_LOCAL_MACHINE > SYSTEM > CurrentControlSet > Control > Terminal Server > ClusterSettings.
2. Under ClusterSettings, find SessionDirectoryListener and make sure its data value is rdp-sxs....
3. If SessionDirectoryListener isn't set to rdp-sxs..., you'll need to follow the steps in the Uninstall the agent and boot loader section to first uninstall the agent, boot loader, and stack components, and then Reinstall the agent and boot loader. This will reinstall the side-by-side stack.

Error: DownloadMsiException

Go to Event Viewer > Windows Logs > Application. If you see an event with ID 3277, that says DownloadMsiException in the description, there isn't enough space on the disk for the RDAgent.

To resolve this issue, make space on your disk by:

• Deleting files that are no longer in user
• Increasing the storage capacity of your VM

Error: Agent fails to update with MissingMethodException

Go to Event Viewer > Windows Logs > Application. If you see an event with ID 3389 that says "MissingMethodException: Method not found" in the description, that means the Azure Virtual Desktop agent didn't update successfully and reverted to an earlier version. This may be because the version number of the .NET framework currently installed on your VMs is lower than 4.7.2. To resolve this issue, you need to upgrade the .NET to version 4.7.2 or later by following the installation instructions in the .NET Framework documentation.

Error: VMs are stuck in Unavailable or Upgrading state

Open a PowerShell window as an administrator and run the following cmdlet:

Get-AzWvdSessionHost -ResourceGroupName -HostPoolName | Select-Object *

If the status listed for the session host or hosts in your host pool always says "Unavailable" or "Upgrading," the agent or stack didn't install successfully.

To resolve this issue, reinstall the side-by-side stack:

1. Open a command prompt as an administrator.
2. Enter net stop RDAgentBootLoader.
3. Go to Control Panel > Programs > Programs and Features.
4. Uninstall the latest version of the Remote Desktop Services SxS Network Stack or the version listed in HKEY_LOCAL_MACHINE > SYSTEM > CurrentControlSet > Control > Terminal Server > WinStations under ReverseConnectListener.
5. Open a console window as an administrator and go to Program Files > Microsoft RDInfra.
6. Select the SxSStack component or run the msiexec /i SxsStack-.msi command to install the MSI.
7. Restart your VM.
8. Go back to the command prompt and run the qwinsta command.
9. Verify that the stack component installed in step 6 says Listen next to it.

Error: Connection not found: RDAgent does not have an active connection to the broker

Your VMs may be at their connection limit, so the VM can't accept new connections.

To resolve this issue:

• Decrease the max session limit. This ensures that resources are more evenly distributed across session hosts and will prevent resource depletion.
• Increase the resource capacity of the VMs.

Error: Operating a Pro VM or other unsupported OS

The side-by-side stack is only supported by Windows Enterprise or Windows Server SKUs, which means that operating systems like Pro VM aren't. If you don't have an Enterprise or Server SKU, the stack will be installed on your VM but won't be activated, so you won't see it show up when you run qwinsta in your command line.

To resolve this issue, create a VM that is Windows Enterprise or Windows Server.

1. Go to Virtual machine details and follow steps 1-12 to set up one of the following recommended images:
   • Windows 10 Enterprise multi-session, version 1909
   • Windows 10 Enterprise multi-session, version 1909 + Microsoft 365 Apps
   • Windows Server 2019 Datacenter
   • Windows 10 Enterprise multi-session, version 2004
   • Windows 10 Enterprise multi-session, version 2004 + Microsoft 365 Apps
2. Select Review and Create.

Error: NAME_ALREADY_REGISTERED

The name of your VM has already been registered and is probably a duplicate.

To resolve this issue:

1. Follow the steps in the Remove the session host from the host pool section.

2. Create another VM. Make sure to choose a unique name for this VM.

3. Go to the Azure portal and open the Overview page for the host pool your VM was in.

4. Open the Session Hosts tab and check to make sure all session hosts are in that host pool.

5. Wait for 5-10 minutes for the session host status to say Available.

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Your issue isn't listed here or wasn't resolved

If you can't find your issue in this article or the instructions didn't help you, we recommend you uninstall, reinstall, and re-register Azure Virtual Desktop Agent. The instructions in this section will show you how to reregister your VM to the Azure Virtual Desktop service by uninstalling all agent, boot loader, and stack components, removing the session host from the host pool, generating a new registration key for the VM, and reinstalling the agent and boot loader. If one or more of the following scenarios apply to you, follow these instructions:

• Your VM is stuck in Upgrading or Unavailable
• Your stack listener isn't working and you're running on Windows 10 1809, 1903, or 1909
• You're receiving an EXPIRED_REGISTRATION_TOKEN error
• You're not seeing your VMs show up in the session hosts list
• You don't see the Remote Desktop Agent Loader in the Services window
• You don't see the RdAgentBootLoader component in the Task Manager
• You're receiving a Connection Broker couldn't validate the settings error on custom image VMs
• The instructions in this article didn't resolve your issue

Step 1: Uninstall all agent, boot loader, and stack component programs

Before reinstalling the agent, boot loader, and stack, you must uninstall any existing component programs from your VM. To uninstall all agent, boot loader, and stack component programs:

1. Sign in to your VM as an administrator.
2. Go to Control Panel > Programs > Programs and Features.
3. Remove the following programs:
   • Remote Desktop Agent Boot Loader
   • Remote Desktop Services Infrastructure Agent
   • Remote Desktop Services Infrastructure Geneva Agent
   • Remote Desktop Services SxS Network Stack

[!NOTE] You may see multiple instances of these programs. Make sure to remove all of them.

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Step 2: Remove the session host from the host pool

When you remove the session host from the host pool, the session host is no longer registered to that host pool. This acts as a reset for the session host registration. To remove the session host from the host pool:

1. Go to the Overview page for the host pool that your VM is in, in the Azure portal.

2. Go to the Session Hosts tab to see the list of all session hosts in that host pool.

3. Look at the list of session hosts and select the VM that you want to remove.

4. Select Remove.

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Step 3: Generate a new registration key for the VM

You must generate a new registration key that is used to re-register your VM to the host pool and to the service. To generate a new registration key for the VM:

1. Open the Azure portal and go to the Overview page for the host pool of the VM you want to edit.

2. Select Registration key.

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3. Open the Registration key tab and select Generate new key.

4. Enter the expiration date and then select Ok.

[!NOTE] The expiration date can be no less than an hour and no longer than 27 days from its generation time and date. We highly recommend you set the expiration date to the 27 day maximum.

1. Copy the newly generated key to your clipboard. You'll need this key later.

Step 4: Reinstall the agent and boot loader

By reinstalling the most updated version of the agent and boot loader, the side-by-side stack and Geneva monitoring agent automatically get installed as well. To reinstall the agent and boot loader:

1. Sign in to your VM as an administrator and use the correct version of the agent installer for your deployment depending on which version of Windows your VM is running. If you have a Windows 10 VM, follow the instructions in Register virtual machines to download the Azure Virtual Desktop Agent and the Azure Virtual Desktop Agent Bootloader. If you have a Windows 7 VM, follow steps 13-14 in Register virtual machines to download the Azure Virtual Desktop Agent and the Azure Virtual Desktop Agent Manager.

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2. Right-click the agent and boot loader installers you downloaded.

3. Select Properties.

4. Select Unblock.

5. Select Ok.

6. Run the agent installer.

7. When the installer asks you for the registration token, paste the registration key from your clipboard.

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8. Run the boot loader installer.

9. Restart your VM.

10. Go to the Azure portal and open the Overview page for the host pool your VM belongs to.

11. Go to the Session Hosts tab to see the list of all session hosts in that host pool.

12. You should now see the session host registered in the host pool with the status Available.

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Next steps

If the issue continues, create a support case and include detailed information about the problem you're having and any actions you've taken to try to resolve it. The following list includes other resources you can use to troubleshoot issues in your Azure Virtual Desktop deployment.

• For an overview on troubleshooting Azure Virtual Desktop and the escalation tracks, see Troubleshooting overview, feedback, and support.
• To troubleshoot issues while creating a host pool in a Azure Virtual Desktop environment, see Environment and host pool creation.
• To troubleshoot issues while configuring a virtual machine [VM] in Azure Virtual Desktop, see Session host virtual machine configuration.
• To troubleshoot issues with Azure Virtual Desktop client connections, see Azure Virtual Desktop service connections.
• To troubleshoot issues with Remote Desktop clients, see Troubleshoot the Remote Desktop client.
• To troubleshoot issues when using PowerShell with Azure Virtual Desktop, see Azure Virtual Desktop PowerShell.
• To learn more about the service, see Azure Virtual Desktop environment.
• To go through a troubleshoot tutorial, see Tutorial: Troubleshoot Resource Manager template deployments.
• To learn about auditing actions, see Audit operations with Resource Manager.
• To learn about actions to determine the errors during deployment, see View deployment operations.