I imported a .mts file into the organizer from a SD memory card.
The video was shot on a Sony NEx-5n and I am using an iMac.
When I play back the video in organizer there is no sound.
I imported that video from Organizer to Premiere and then the sound was ok.
Does organizer support sound for .mts files? (I also imported Mp4 video from the same camera into organizer and the sound was just fine)
Yes, the Organizer will play back the sound on your MTS files -- though you may need to activate a component first.
Start up a new project in Premiere Elements and add one of your MTS video clips to the beginning of the timeline. You should NOT see a yellow orange "render" line above this clip. If you do not see this render line, add your other MTS files to the timeline. The program will indicate in the lower right that these files are conforming. Once they are fully conformed and the program has activated the necessary components, the files should play fine in your Organizer.
The one contingency is the operating system you're using.
If you are using Sierra, things get a bit more complicated as the Apple is still working the bugs out of this OS.