title: Android Studio - Device is connected but 'offline'
body: <p>This is quite a common question, but none of the solutions appear to work for me. First time asker, so apologies if I get the conventions wrong.</p>
  
  <p>I am trying to connect my Galaxy S5 to my computer running Ubuntu 14.04 so I can do some android development. I have recently downloaded and installed Android Studio and the SDK and my device is detected when it's connected via USB but the device either appears as 'unauthorized' or 'offline'. I know I should be expecting the RSA key prompt but this never appears.</p>
  
  <p>I have tried:  </p>
  
  <ul>
  <li>Checking debugging was enabled  </li>
  <li>Running adb kill-server and adb devices  </li>
  <li>Restarting (the device, developer options, the machine)  </li>
  <li>Simple unplugging and replugging the USB cable </li>
  <li>Checking my adb version (it is 1.0.31)  </li>
  <li>Trying different USB ports  </li>
  <li>Revoking USB debugging authorizations</li>
  <li>Toggling enabling ADB Integration from within Android Studio</li>
  <li>Connecting as PTP device and MTP device</li>
  </ul>
  
  <p>I have tried it on a separate machine that runs fedora and this works fine with no issues, the promopt appears right away. Therefore I imagine it is not the USB cable that is faulty.</p>
  
  <p>Any ideas?</p>