Export the vm in VirtualBox, thereby you create a .VMDK file, which basically is a virtual harddisk. Although, VMplayer works with .VDMK files you have to configure a .VMX file in order to run it.
If you own a VM Workstation edition you just create a new virtual machine and select your .VDMK when you are ask to create a new or select an existing virtual machine disk.
In case you set the option “dynamically resizeable” in VirtualBox you might want to try these instructions. Here are the main steps to undertake this mission:
Convert your .VDI to a .raw image by the vboxmanage shell command:
vboxmanage internalcommands converttoraw .VirtualBox/HardDisks/myvm.vdi vmware/myvm.raw
Convert the .raw image to a .VMDK file:
qemu-img convert -O vmdk myvm.raw myvm.vmdk
Create a VM with VMplayer and exchange the .VMDK with your own, either by renaming or changing the config in the .vmx file.
Make sure your user has read rights to the .VMDK or is owner.
Problems running VirtualBox and VM software
Running VirtualBox and VMplayer or the like in parallel leads to problems, e.g.
VirtualBox can’t operate in VMX root mode. Please disable the KVM kernel extension, recompile your kernel and reboot (VERR_VMX_IN_VMX_ROOT_MODE).
If you execute the VM software and then want to start a vm out of VirtualBox you will have to disable your KVM like this:
sudo rmmod kvm-intel # for intel processors sudo rmmod kvm-amd # similar for amd
To enable the KVM module again just type
modprobe kvm-intel modprobe kvm-amd
in your shell.