The best option is to export and import the VM in OVA (Open Virtual Appliance) format, but there is no GUI option to export in Fusion. This time the need was to move a Windows 8.1 virtual machine from VMware Fusion for OS X 10.9.4 to VirtualBox on Linux.
Need to do something, dig the Net, take a while to find stuff so I think to make a note on my… virtual hints book 😉 The main reason of almost every post on this blog is the same.