Network Outage Due to Invalid vmxnet3 Driver After Windows Server 2019 Update
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Network Outage Due to Invalid vmxnet3 Driver After Windows Server 2019 Update

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Article ID: 414290

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

After applying Windows Updates on a Windows Server 2019 virtual machine (VM), the network connection may be lost.

  • Inability to connect to the VM via Remote Desktop (RDP).
  • Inside the VM, the network adapter shows as an "Unidentified Network" or has no connectivity.
  • In Device Manager, the vmxnet3 network adapter may appear with a yellow bang or triangle.
  • Vmxnet3 adapter is not available or has failed suddenly.
  • E1000E adapter is not affected.

Environment

  • Microsoft Windows Server 2019
  • Vmxnet3 Network Adapter

Cause

The root cause is a conflict between the Windows Update process and the VMware Tools upgrade process.

  1. Some Windows Updates (particularly cumulative updates or those affecting core components like the .NET Framework or system kernel) require multiple reboots to complete the installation.
  2. If VMware Tools is upgraded before these pending Windows reboots are performed, the system is in an inconsistent or "half-updated" state.
  3. Installing VMware Tools in this state can cause the vmxnet3 driver installation to fail or become corrupted, resulting in an invalid driver and a subsequent network outage.

Resolution

If you are currently experiencing this issue, follow these steps to restore network connectivity:

  1. Access the VM Console: Use the vSphere Client or ESXi Host Client to open a console session to the affected VM, as network access is unavailable.
  2. Repair VMware Tools:
    1. Within the VM, go to Control Panel > Programs and Features.
    2. Locate VMware Tools in the list of installed programs.
    3. Right-click on it and select Uninstall/Change.
    4. In the VMware Tools installation wizard, choose the Repair option.
    5. Follow the prompts to complete the repair and restart the VM when prompted.
  3. Verify Resolution:
    1. After the reboot, check if network connectivity has been restored.
      1. Open Device Manager and confirm that the yellow bang on the vmxnet3 adapter is gone and the device status is normal.
    2. If the above process did not resolve the issue, perform the following procedure to uninstall the vmxnet3 driver and reinstall it via VMware Tools:
      1. Take a snapshot of the VM, and note the existing networking configuration (assigned portgroup, assigned IP, subnet mask, etc.).
      2. Power off the VM and remove the existing vmxnet3 adapter from the vSphere client.
      3. Power on the VM, and head back to Device Manager to see if there are any vmxnet3 devices (View -> Show hidden devices).  There should be at least one.
        1. Right-click the vmxnet3 adapter entry and click Uninstall device -> tick the checkbox "Attempt to remove the driver or this device" -> Uninstall.
        2. Uninstall any other vmxnet3 adapters.
        3. Reboot the VM.
      4. Uninstall VMware Tools from the Add/Remove Programs Wizard.
        1. Reboot the VM.
      5. (Re)Install VMware Tools via your preferred method (ISO, via the banner in the vSphere Client page for the VM, etc.).
        1. Reboot the VM.
      6. Back in the vSphere client, assign a new Network Adapter, ensuring that you select a vmxnet3 Adapter Type from the dropdown (as the default would be an E1000E), and select the proper portgroup.
        1. Check Device Manager once more to see that the device is operating normally.
        2. Proceed with IP assignment/configuration.
      7. Remove the snapshot when comfortable that the issue is resolved.

Prevention and Best Practices

To prevent this issue from occurring in the future, always adhere to the following maintenance sequence:

  1. First, upgrade VMware Tools.
    1. Ensure VMware Tools is upgraded to the latest version before initiating any Windows Updates.
    2. Restart the VM immediately after the upgrade to load the new drivers.
  2. Then, uerify vmxnet3 driver status.
    1. After the reboot, log in and open Device Manager.
    2. Confirm that the vmxnet3 network adapter is functioning correctly without any warnings.
    3. Verify that the driver version is correct and reported as healthy.
  3. Finally, Perform Windows Update.
    1. Only after confirming the network adapter is stable, proceed with installing Windows Updates.
    2. Crucially: If the system requires a restart, perform it immediately. Some updates may require more than one reboot. Continue restarting until the system no longer prompts for one, confirming all updates are fully installed.

Summary Workflow:

Upgrade VMware Tools -> Restart VM -> Confirm vmxnet3 driver is healthy -> Run Windows Update -> Perform all required restarts

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