A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
I bet that it is playing across slides. There appears to be a bug where neither the Trim or Fade functions work if combined withe tick the box "play across slides". 100% replicatable. Wish it were patched already!! Where I am trying to use it is to do a slideshow for a 60th birthday with lots of photos and captions, and have snippets of music from various MP3 or WAV files fade in and out, but each snippet covering a number of slides. Thanks Andrew McKenzie --- for the search crawlers. Powerpoint 2010 problem: Trim and Fade do not work with Playback Start option "play across slides"