I've looked through post upon post about possible solutions and I've tried them all (check VM settings / filters, download guest additions, installing Vbox extension pack, making sure my username is part of the group 'vboxusers', downloading the most recent version of VirtualBox NOT in Software Centre, making sure device is unmounted in host OS) and still had no luck. My Webcam for whatever reason is fully integrated but whenever I go to 'USB devices' there's nothing listed so it won't let me create any USB filters. Any suggestions would be appreciated. P.S. I'm using ubuntu 15.10 and VirtualBox 5.0.10 and my guest OS is Windows 8.1 64-bit (not that I think it matters).
I had this issue several times with USB Devices and it was always a problem with the USB 2.0 Support in VirtualBox. Go to Settings -> USB and try the different compatibility options available there.
Hope it helps