The way giving the best compatibility to migrate your Virtual Machines from VMware to VirtualBox is to convert them in Open Virtualization Format (.ovf) first.
To do so, VMWare provides an OVF Tool (see User Guide) which is embedded in some recent versions of Workstation and Player.
If you don't have such version, download the OVF Tool version corresponding to your host.
For better compatibility, according to the guest OS there is some instructions to perform first (you may get more information reading this forum or this article) like:
- uninstall vmware-tools
- remove hardware like sound card(s), floppy drive(s), CD/DVD drive(s) (at least unmount iso file), additional IDE controller(s)
Just before converting, you should (otherwise you may get a generic error "Failed to open disk"):
- prepare a destination folder with enough free space
- ensure having rights to read source Virtual Machines, and to write in the destination folder
- switch off Virtual Machine to convert
- ensure there is no lock file/directory in the Virtual Machine directory (with .lck extension); otherwise restart it with VMware and stop it properly (at worst, delete the .lck file/directory)
Then, you can convert your Virtual Machine to Open Virtualization Format:
ovftool /path/to/VMware/VM.vmx /path/to/VM.ovf
Finally, you can import this "new" Virtual Machine in VirtualBox:
- check first you have configured the storage of Hard Disk Drives and Virtual Machines (see preferences) to ensure having enough free space (by default, they are stored under your home directory).
- configure the Virtual Machine: name, operating system, architecture, network mode; and finally add every hardware you need.
- start the Virtual Machine under VirtualBox to ensure it works perfectly.
If it is the case, you can delete the VMWare version and Open Virtualization Format version which are no more needed.