VirtualBox and USB devices, vboxusers.

By default when installing VirtualBox on Ubuntu, you won’t be able to access USB devices in the VM.

To get around that problem is very simple, below are listed the steps needed to get access to USB devices in the VM.

First, make sure you have the latest version of the software:
Download VirtualBox

You also need to install the extension pack:
Get Extension Pack

and the Guest Additions:

Guest Additions Manual

After installing all the extra dependencies, it is time to enable USB access to the VM.

First

Right click on the VM and select settings:

You will get this message:

Failed to access the USB subsystem

VirtualBox is not currently allowed to access USB devices. You can change this by adding your user to the ‘vboxusers’ group. Please see the user manual for a more detailed explanation.

It tells that you need to add your user to the vboxusers group.

Second

There are two ways to add users to groups in Ubuntu.
Via the GUI

If you want something faster, it is also possible to add a user to a group via the command line:

After adding the user to the vboxusers group you need to restart Ubuntu.

Third

Now after adding the user to the vboxusers group, it is time to select which USB device you want to mount in the VM

Forth

Access USB devices in the VM

More Info:
http://www.howtogeek.com/howto/31726/mount-usb-devices-in-virtualbox-with-ubuntu/