When a virtual machine is powered on, Workstation Pro assigns each of its virtual network adapters an Ethernet media access control (MAC) address. A MAC address is the unique address assigned to each Ethernet network device.

A virtual machine is assigned the same MAC address every time it is powered unless the virtual machine configuration (.vmx) file is moved or changes are made to certain settings in the configuration file.

Moving the file to a different host system, or even moving it to a different location on the same host system, changes the MAC address.

The MAC address changes if you remove or change any of these options in the virtual machine configuration (.vmx) file.

  • ethernet[n].generatedAddress

  • ethernet[n].addressType

  • ethernet[n].generatedAddressOffset

  • uuid.location uuid.bios

  • ethernet[n].present

In these options, [n] is the number of the virtual network adapter. If you never edit the configuration file by hand and do not remove the virtual network adapter, these settings remain unchanged.

Workstation Pro cannot guarantee to automatically assign unique MAC addresses for virtual machines that run on multiple host systems.


To preserve the MAC address for a virtual network adapter, you must be careful not to remove the adapter. If you remove the adapter but later recreate it, the adapter might receive a different MAC address.