VMware Fusion 4 to VirtualBox

There are two things representing a VM:

• Disk image file(s)
• Configuration (paths to disk images, network interfaces, resource allocation, like RAM and CPUs, etc...)

The disk image part is a piece of cake, as VirtualBox supports VMware's disk images: VMDK (open format). So you can use your .vmdk file(s) as-is.

Regarding the configuration part, you'll have to create a new VM from scratch in VirtualBox (pointing to the existing .vmdk files, of course), you're free to change any resource allocation.

Things to be wary about: the two hypervisors expose different brand/model virtual hardware devices to the guest. The guest OS may detect new devices, you will have to install the appropriate drivers.

 

What the poster above means is that this is similar to moving a hard drive between two different computers. The computer configuration (devices, etc) are going to be somewhat different, so the guest OS in the virtual machine might ask you to install drivers or will detect a change in the system.

You will be able to control and change all the system settings (RAM, CPU cores, etc) in VBox.

I am a big fan of VBox and have used it very extensively in the past couple of years. For the price (free for personal use), it is a great product.

 

By "hypervisors", I meant Fusion and VirtualBox.

The reason why the guest OS will see different hardware is not because of the move to a new host computer, it's because of the different emulated hardware devices in VirtualBox compared to Fusion. Though I think both are originally forked from QEMU so chances are they're still roughly the same brand/models.