Wasp has received reports of wired USB scanners no longer working after upgrading to Mac OS X 10.11 (El Capitan). The scanner beeps, then is unresponsive.

 

Users on Apple's discussion forums have also reported problems with other non-Wasp scanner models:

 

As of December 2, 2015, our hardware engineers have confirmed that Apple has changed the communication method, and are working on a solution.