First of all, you need to install VirtualBox Guest Additions package and VirtualBox Extension Pack for your copy of the program. Extension Pack is a set of utilities designed to improve the interaction between the user and the virtual machine, and it needs to be installed in VirtualBox. In the window About, check the build number and download the corresponding package from the official FTP server. Chose an active virtual machine, click File - Preferences in the top menu and go to Extensions. After that, click on the button with the arrow, give the path to the package you have just downloaded from the FTP server, and install the package. Before you start the virtual machine, go to its main menu and open Settings, go to USB and check the options for Enable USB Controller and SB 2.0 (EHCI) Controller. Also, create a filter for the required USB device by choosing it on the list of all available USB drives, regardless if these are external hard disks or flash drives.