Oracle VM VirtualBox uses XML for both the machine settings files and the global configuration file, VirtualBox.xml.

All Oracle VM VirtualBox XML files are versioned. When a new settings file is created, for example because a new virtual machine is created, Oracle VM VirtualBox automatically uses the settings format of the current Oracle VM VirtualBox version. These files may not be readable if you downgrade to an earlier version of Oracle VM VirtualBox. However, when Oracle VM VirtualBox encounters a settings file from an earlier version, such as after upgrading Oracle VM VirtualBox, it attempts to preserve the settings format as much as possible. It will only silently upgrade the settings format if the current settings cannot be expressed in the old format, for example because you enabled a feature that was not present in an earlier version of Oracle VM VirtualBox.

In such cases, Oracle VM VirtualBox backs up the old settings file in the virtual machine's configuration directory. If you need to go back to the earlier version of Oracle VM VirtualBox, then you will need to manually copy these backup files back.

We intentionally do not document the specifications of the Oracle VM VirtualBox XML files, as we must reserve the right to modify them in the future. We therefore strongly suggest that you do not edit these files manually. Oracle VM VirtualBox provides complete access to its configuration data through its the VBoxManage command line tool, see VBoxManage and its API, see .