Why doesn't slideshow preview play the music from your start location? Sound is blank unless you start the preview from the very first slide, w hich is annoying for large slide shows where you need to time the music. I couldn't get preview to work at all (showing black photos until I set Run as Administrator in the .exe properties. Never had to do these things with PE 9 or 10.
Which version of Windows OS are you on? Does the issue happen for slideshows created with any file type? or it happens when you use large files only?
Is the account you are currently working on a Standard user account?