"Physical Network Adapters Warning" when creating a virtual switch

Products

• VMware vSphere ESX 8.x

Issue/Introduction

• When using the Add Networking wizard to create a new vSphere Standard Switch (VSS) or Distributed Switch (VDS), the following alert is displayed:  
  

  Physical Network Adapters Warning: There are no active physical network adapters for the switch. Click OK to continue or Cancel to review your changes.

  
  ^^^This alert is a validation check of the configuration selection, not a status report of the physical hardware.
  
  
• The physical network adapters, including any vmnic(s) intended for use on the new switch, are visible in the Unclaimed adapters section.
  
  
• The warning prevents completing the Wizard to add the new switch.
  
  
• Outside of the wizard, the adapters show as "Connected" or "Up" under the Host Configure > Networking > Physical adapters view.
  
  
• The adapters correctly negotiate speed (e.g., 10000 Mbps) and duplex (Full), and the physical link lights on the NIC/Switch port are active.
  
  
• Running esxcli network nic list on the host confirms the Link status is Up and the Admin status is Up, indicating no underlying driver or physical connectivity issues.

 

Cause

• The vSphere Client wizard triggers this validation alert if no physical adapters have been explicitly assigned to the "Active" or "Standby" uplink groups.
  
  
• By default, even if adapters are highlighted or selected in the "Unclaimed" list, they are not yet considered "Active" by the wizard's logic.
  
  
• The UI will prompt this warning anytime the Active adapters pool is empty during a configuration change as well as when creating a new switch.

Resolution

Perform these steps to correct the virtual switch configuration:

1. In the Add Networking wizard, navigate to the Teaming and Failover or Select Adapters step.
   
   
2. Locate the Unclaimed adapters section.
   
   
3. Select the physical adapter (e.g., vmnic0) you intend to use as an uplink.
   
   
4. Click the MOVE DOWN action link (for Standard Switches) or use the Assign Uplink button (for Distributed Switches).
   
   
5. Verify the adapter is now listed under the Active adapters section.
   
   
6. Click Next. The warning will no longer appear, and you can complete the configuration.

Additional Information

• This alert may also appear when modifying an existing Standard Switch (VSS) or Distributed Switch (VDS) via Edit Settings > Teaming and Failover.
  
  
  • If all previously assigned adapters are moved to the "Unused" or "Unassigned" categories, or if an existing uplink is removed without a new one being moved to "Active," the same Physical Network Adapters Warning will trigger upon clicking OK or Save.
    
    
  • This is intended to prevent users from accidentally disconnecting all network traffic (including Management or vMotion) from the physical network.
    
    
  • The resolution is the same but done via Edit Settings rather than the wizard for adding a new switch:
    
    
    • Standard Switch: in the Standard Switch Edit Settings menu under the Teaming and Failover section.
      
      
    • Distributed Switch: in the Edit Settings dialog for the Distributed Port Group or Uplink Port Group.