how to remove stuck USB device

power off laptop

use needlenose pliers to remove stuck piece

Make sure you remove the battery and unplug the system before doing anything.  It may also help to leave the notebook in a cold room (minus the battery) for a while before you try to remove the sleeve.

Thanks for reminding me to remove the battery.  As I noted in response to ieee488, I can't get any grip on the sleeve.  I haven't tried the cold room yet, but maybe that's next.  (I've also ordered a 4-port hub so I'm not stuck with one 3.0 and one 2.0 port.

Thanks for the suggestion, but I've tried needlenose pliers, and there's just not enough space between metal sleeve and port housing to get any grip.

You may have to remove the i/O board or the system board to get to the port and do the repair:

Thanks for the link.  Two questions: 1. Although I've mucked around inside a desktop, I haven't worked inside a laptop.  Is this a tricky move?  2. The laptop is still under warranty.  Is it risky to mess with the laptop and potentially void the warranty?  (I'm assuming the problem with a USB device is not the sort of thing covered by the warranty itself.)

Any damage done won't be covered by the warranty - and it's unlikely the removal of the cable components would be covered.  If you're worried about that, Dell will likely charge about $150 flat rate to do the repair.  That's probably close to what a competent computer shop would charge - with of course the assurance that the warranty will remain in effect.