VirtualBox: USB device is busy with the previous request
You need to install the VirtualBox Guest Additions, you may need to install virtualbox-guest-utils and your corresponding virtualbox-guest-modules (please check this part of the arch awesome wiki )
You have also to check whether your username is part of the group vboxusers.
Last thing, you may want to check if USB 2 (or 3) is being supported by your hypervisor otherwise you have to install an extension pack, please refer to this part of the wiki