Failure of Leonard Arduino board

I am using a MacAir computer, I connect an Ardunio UNO board, no problem. Upload programs and all is well. I remove UNO and install Littlebit module and NOTHING!. total failure. So I requested a replacement Littlebit module…it came…same problem. UNO works and same USB port Littlebit is dead. Yellow lites flash (yes I am using remote power 9 v and line adapter…both power up, yellow lites flash but LED module will not BLINK. Nothing loads to the Littlebit. Frustrating. Any help out there?
Glenn

Sorry to hear you’re having trouble even after getting a replacement. I’m going to run this issue by a couple of our engineers. Thanks for posting!

Have you tried the Arduino 1.5.8 (beta) release? There was a change Apple made at some level that impacted the current IDE release, and it’s ability to work with some Arduino boards. There’s a fix in the 1.5.8 release.

Just a thought,
Kevin

Remember it is a Leonardo, not an Uno.