TPM not detected in Windows 11 24H2 VDI VMs

Products

• VMware vSphere ESXi

Issue/Introduction

A virtual machine running Windows 11 24H2 in a may fail to detect the virtual Trusted Platform Module (vTPM).

• The VM has the Omnissa Horizon agent installed.
• Windows Device Manager shows the Trusted Platform Module as present
• However, when querying the TPM, either using the PowerShell commandlet Get-Tpm or with the tpm.msc management console snap-in, the TPM is not detected.

Environment

• VMware vSphere ESXi 8.0.x
• Microsoft Windows 11
• Omnissa Horizon agent

Cause

This issue has been observed when Serial Port Redirection is enabled in the Horizon Agent.

Resolution

To resolve this issue, disable Serial Port Redirection for the Omnissa Agent, using either of the following options:

1. By modifying the Horizon Agent Installation:

   Serial Port Redirection is an optional component and is deselected by default during a standard installation. If it was previously enabled, the feature can be removed by modifying the installation:
   1. On the master image or virtual desktop, go to Control Panel → Programs and Features.
   2. Select Omnissa Horizon Agent and click Change/Modify.
   3. Progress to the Custom Setup page and locate Serial Port Redirection.
   4. Click the dropdown next to it and select Entire Feature will be unavailable.
   5. Complete the wizard and restart the machine.

   
   Note: When a silent installation script is used to deploy the agents, ensure that SerialPortRedirection is not included in the ADDLOCAL parameters.
   
   

2. By disabling the feature via Group Policy (GPO):

   To suppress the feature across an entire environment without altering the baseline image, it can be locked down using the Horizon Agent ADMX templates (vdm_adgent.admx).
   1. Open the Group Policy Management Editor.
   2. Navigate to Computer Configuration</ → Policies → Administrative Templates → Omnissa Horizon Agent Configuration → Serial COM.
   3. Locate the policy setting designed to deactivate the feature (usually Disable functionality or Disable Serial Port Redirection).
   4. Set the Policy to Enabled and apply it to the Organizational Unit (OU) containing the Horizon Agents

Following either of these actions, verify that the TPM is being properly detected by either using the Get-Tpm commandlet in PowerShell, or by checking via the tpm.msc snap-in.

For further assistance, contact Broadcom support.

Additional Information

For more information related to serial port redirection, see Configuring Serial Port Redirection in the Omnissa documentation.