I using ubuntu in virtualbox, and when connect to usb device, I can see them using lsusb, however it is not mount in anywhere, and fdisk -l also didn't show any external device. What did I do wrong and how can I access to my usb
Thanks
What is the guest OS type? if it's Win7 then;
(assuming you've already installed guest additions)
You need to set USB filters so that the USB devices get sent to the guest OS.
From the main Virtualbox window open the Settings dialog, then the USB section, then click the little "add filter" button on the right side of the screen. You should be able to create a filter from any currently connected USB devices.
After you've done this (maybe restart to be sure the host OS isn't capturing any of the USB devices for itself--Ubuntu will try to automount the flash drive so you might also want to check and make sure that it is unmounted too) then boot into the guest OS and you should see your USB devices
Hope that helps