This is a known issue that our Development team is currently looking into.
Behavior: When attempting to stop a recording from TechSmith Relay after recording a Powerpoint or Keynote presentation (in presentation mode) on Mac OS X, will result in the Relay Recorder crashing or hanging.
Workaround: Once the presentation is over, completely exit out of Powerpoint or Keynote before stopping the recording in Relay. This should allow the recording to finish correctly.
*Note: This also applies to Camtasia for Mac.