title: Virtualbox: "USB device in use by someone else" error, how to make (mac) host let go?
body: <p>I'm trying to set up a USB Fax Modem in Ubuntu through Virtual Box but I'm not sure how to do so. </p>
  
  <pre><code>Host OS = Mac OS X
  Virtual Box Guest OS = Ubuntu 12.04
  56k USB Fax/Modem = Lenovo 43R1786 (43R1815) by Conexant
  </code></pre>
  
  <p>On the host os, I can see /dev/tty.usbmodem24680241. I enabled USB Controller, and found my modem as "Conexant USB Modem", so I enabled that. Now, when I run the guest OS, and from the Virtual Box menu for that OS, I go to Devices > USB Devices > Conexant USB Modem, it says:</p>
  
  <p>Failed to attach the USB device Conexant USB modem to the virtual machine Ubuntu32. USB device is in use by someone else. Looks like it means that the host (mac) grabbed the device first. How can I get it to let go so the guest can use it? Am I setting it up the right way?</p>
  
  <p>Thanks!</p>