Samsung Galaxy S III (S3) Won't Connect via USB with Android File Transfer with MacBook Pro - Mountain Lion
https://discussions.apple.com/thread/4163985?start=0&amp;tstart=0
Android File Transfer worked with S3 on Mac running Snow Leopard once I used the right cable! 
I discovered I had 2 different type USB cables- one seems to just charge and so Android File transfer didn't recognize the phone at all. The other cable, bearing the Verizon label, was entirely different. Please see link above and go to my posting under Interpret for full explanation.

Post from linked site:


  As already mentioned, download and install Android File Transfer app . NOTE: To connect be sure to use the right cable- in my case, I discovered 2 cables - one is a USB plain one that just charges the phone. After much frustration I discovered there was another one (it has a Verizon label in my case.) They both seem to be USB cables but I discovered one works with Android File Transfer and not the other.
  
  When I connected the wrong one, Android File Transfer said: No Android device found. Please connect your Android device with a USB cable to get started. I wasn't getting any notification or option on my phone to switch any configuration menu.
  
  When I switched to the right cable however, I got a notification in the top notification area of the phone stating:
  
  Connected as an installer and a USB icon next to it. Swiping down the top notification part there was yet another notification stating Connected as a media device. Touch for other USB options. Tapping on that statement I got the following screen:
  
  USB PC Connection
  
  Connect as
  
  Media Device (MTP) box to check
  
  xxx explanatory text which mentions you can sue Android File Transfer on a Mac in this mode
  
  Camera (PTP) box to check
  
  xxx explanatory text (transfer to PC that does not support MTP)
  
  (Note that these options were not available and not displayed with the wrong cable. I noticed many users stating they don't see that menu, wonder if the culprit is the cable being used.)
  
  I checked off MTP box and voila, clicking on the Android File Transfer icon I could see  the files organized under Phone and Card and had access to them.