This is done on the Linux CLI
Extract OVA
tar -xvf example.ova
Check for term virtualbox
cat *.ovf | grep virtualbox
Remove it in place vm vmx-# (#=VMware VM Version/Generation)
sed -i -e 's/virtualbox-2.2/vmx-11/g' *.ovf && chmod 777 *
Prove virtualbox is gone
cat *.ovf | grep virtualbox
Credit : http://www.baconapplications.com/export-a-virtualbox-machine-to-vmware/
Uninstall VirtualBox Guest Additions via
sudo mount /dev/cdrom1 /mnt/cdrom
sudo /mnt/cdrom/VBoxLinuxAdditions.run uninstall