Hot adding a network adapter to a virtual machine fails with the error: Communication with the virtual machine may have been interrupted

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• Cannot hot add a network adapter or an USB controller to a virtual machine
• Hot adding a network adapter or an USB controller to a virtual machine fails
• You see the error:
  
  A general system error occurred: The system returned an error. Communication with the virtual machine may have been interrupted.
  
  
• You are able to add a disk or SCSI controller

Environment

VMware ESX 4.1.x
VMware ESXi 4.1.x Installable
VMware ESXi 4.1.x Embedded
VMware vCenter Server 4.1.x

Resolution

This issue occurs if the devices.hotplug option for the virtual machine is set to false. When this option is set to false, you cannot hot remove devices from the operating system or hot add devices, such as network adapters or USB controllers, to the virtual machine.

To resolve this issue:

1. Power off the virtual machine.
2. Open the .vmx file using a text editor.
3. Delete or comment the devices.hotplug entry in the .vmx file. For more information, see Tips for editing a .vmx file (1714).
4. Power on the virtual machine.