Unable to successfully install Windows Admin Center (Preview) on Azure Arc

I solved this exact issue by avoiding the failed “Connect” deployment completely and doing a clean manual installation of Windows Admin Center.

The error WAC_Installer_Error_Failed_To_Initialize usually happened because the automatic installer could not properly initialize on the server. What fixed it was removing the failed installation remnants, enabling TLS 1.2, and installing WAC manually as Administrator.

Here is exactly what I did:

1. Rebooted the server.
2. Opened PowerShell as Administrator and enabled TLS 1.2: [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
3. Deleted any failed Windows Admin Center installation folders: C:\Program Files\Windows Admin Center\
   1. and cleared temporary files from: C:\Users<username>\AppData\Local\Temp\
4. Downloaded the latest Windows Admin Center installer directly from Microsoft instead of using the “Connect” button: https://www.microsoft.com/en-us/windows-server/windows-admin-center?utm_source=chatgpt.com
5. Run Installer as administrator
6. Installed it using a different port (6520 instead of the default 6516) because the original port was conflicting with another service.
7. Rebooted the server again after installation. After that, Windows Admin Center opened successfully through: https://ServerName:6520, and the installation completed without the initialization error.

I am confident this will work. Try it.

Hello 石田 茂人,

Welcome to the Microsoft Q&A and thank you for posting your questions here.

I understand that you are unable to successfully install Windows Admin Center (Preview) on Azure Arc.

The error: WAC_Installer_Error_Failed_To_Initialize (1). Specifically, made us to know that the root cause of this issue is typically a combination of Arc agent incompatibility, PowerShell environment misconfiguration, and restricted outbound connectivity, all of which can prevent the WAC extension installer from initializing correctly.

The best professional advice for resolution is to:

• Upgrade the Azure Connected Machine Agent to a supported version (1.37 or later) to eliminate known compatibility issues that disrupt WAC deployment - https://learn.microsoft.com/en-us/windows-server/manage/windows-admin-center/azure/manage-arc-hybrid-machines
• Restore the PowerShell module path (PSModulePath) to fix module loading failures that block installer initialization - https://learn.microsoft.com/en-us/windows-server/manage/windows-admin-center/support/troubleshooting
• Ensure required outbound connectivity (TCP 443) and allow Azure Arc service endpoints, including the WindowsAdminCenter service tag and Service Bus WebSockets communication - https://learn.microsoft.com/en-us/azure/azure-arc/servers/network-requirements, https://learn.microsoft.com/en-us/azure/azure-arc/network-requirements-consolidated
• Remove any failed or partial WAC extension deployment and reinstall it cleanly from the Azure portal

After applying these corrections, the Windows Admin Center extension installs successfully, and the Azure portal “Connect” action completes without further errors. All the resources links gives you more steps and reading insights.

I hope this is helpful! Do not hesitate to let me know if you have any other questions, steps or clarifications.

Please don't forget to close up the thread here by upvoting and accept it as an answer if it is helpful.

Hello 石田 茂人,

Thank you for reaching out to the Microsoft Q&A forum.

When investigating it looks like the Windows Admin Center (WAC) preview extension on your Arc-enabled server is hitting a “WAC_Installer_Error_Failed_To_Initialize” which means the installer couldn’t start on the hybrid machine. Here are a few things to check/fix:

Confirm prerequisites are met on your server

• Windows Server 2016 or later
• At least 3 GB RAM
• Azure Connected Machine (Arc) agent v1.13.21320.014 or later

Verify Azure permissions

• To install, your user needs Owner, Contributor, or Windows Admin Center Administrator Login on the Arc resource
• To connect, you need Reader + Windows Admin Center Administrator Login

Check the WAC extension version

• In the Azure portal, go to your Arc server → Extensions → “AdminCenter”
• Ensure version is 0.0.0.169 or higher. If not, uninstall and reinstall the extension.

Make sure the Windows Admin Center service is running

• RDP into the server, open Task Manager → Services
• Look for ServerManagementGateway / Windows Admin Center and start it if it’s stopped

Validate reverse-proxy port configuration

In PowerShell on the server, run:

azcmagent config list

Confirm your WAC port (default — 6516, or your custom port) appears under incomingconnections.ports

If it’s missing, add it:

azcmagent config set incomingconnections.ports <your-port>

Restart the HIMDS service, In an elevated PowerShell prompt:

Restart-Service Himds

Ensure outbound internet connectivity to these endpoints:

*.wac.azure.com (or WindowsAdminCenter service tag)

pas.windows.net

*.servicebus.windows.net

If it still fails, collect detailed logs for deeper troubleshooting

• Portal logs: Go to Extensions → AdminCenter → View Detailed Status
• Agent logs: On the server run azcmagent logs and zip up the output

As a last resort, remove/reinstall the extension via PowerShell:

• Remove-AzConnectedMachineExtension -Name AdminCenter
• Install-AzConnectedMachineExtension -Name AdminCenter

Give those steps a shot and let us know if the installer gets past the initialization phase or if new errors pop up.

Let me know if any further queries - feel free to reach out!

References

• Manage Azure Arc–enabled servers using Windows Admin Center https://docs.microsoft.com/windows-server/manage/windows-admin-center/azure/manage-arc-hybrid-machines#troubleshooting
• Remote access with Windows Admin Center for Arc-enabled servers https://docs.microsoft.com/windows-server/manage/windows-admin-center/azure/manage-arc-hybrid-machines
• Assign Azure roles in the portal https://docs.microsoft.com/azure/role-based-access-control/role-assignments-portal