If the wrong VirtualBox package was installed, the following error will pop up when starting a virtual machine. Please check the instructions just above to install the correct package for your kernel.
On the guest Machine, open `Files` and click on the optical drive icon (CD name starts with VBOXADDITIONS) then click on the `Run Software` button and follow the on screen instructions.
Virtual machines are created with only 1 CPU. You can change this in
`System` -> `Processor`
#### 3D Acceleration
For better performances, it is strongly recommended to enable 3D Acceleration in `Display` -> `Screen`
#### USB Controller
If you have installed the [extension pack](https://www.virtualbox.org/manual/ch01.html#intro-installing) and your hardware supports it, you set the USB Controller to USB 2.0 or 3.0, in `USB`
Note: Access to USB is granted by the user group `vboxusers` on the **Host** operating system. You can add yourself to this group with the following command
You can share folders from the Host to the Guest in `Shared Folders`
**Note:** auto-mounted shared folders are mounted into the `/media` directory, along with the prefix `sf_`. For example, the shared folder `myfiles` would be mounted to `/media/sf_myfiles`. Access to auto-mounted shared folders is only granted to the user group `vboxsf` on the Guest operating system.