Sun’s Virtualbox supports VMWare VMDK files (virtual hard drives) however when booting from a vmdk file a couple of things must usually be done to prevent the virtual machine from hanging when booting up.

1. Booting in safe mode will reveal that the system hangs at the c:\system32\drivers\agp440.sys file. There are a variety of ways around this but the simplest (yet not the cleanest) way is to boot in recovery mode (or from another VM with the vmdk mounted as a second drive) and delete the agp440.sys file.

2.  After rebooting with the vmdk file the system will likely hang at the Mup.sys file. This is a simple fix, in the VM’s System settings make sure the “Enable IO APIC” checkbox is checked.

For a more detailed explanation with other migration tips please see Vmware to Virtualbox Migration Issues.