Background sound stops playing in a presentation when the presentation reaches a slide that uses built-in custom animation with sound effects in PowerPoint

Consider the following scenario:

• You use Microsoft PowerPoint to create a presentation that has multiple slides.
• You add a .wav background sound file to the presentation.
• You configure the background sound file to play across multiple slides in the presentation.
• You add a slide that uses built-in custom animation with sound effects to the presentation.

When you view the presentation, the background sound stops playing when the presentation reaches the slide that has built-in custom animation with sound effects. Only the custom animation sound effects are played.

This issue may occur if the background sound file is embedded in the presentation. By default, you cannot play two embedded sound files at the same time in PowerPoint. You can play two sound files at the same time only if the sound files are linked sound files.

The size of the sound file determines whether PowerPoint treats the sound file as a linked sound file or as an embedded sound file. You can specify the default size setting for linked sound files. Sound files that are larger than the size that you specify are linked to the presentation. They are not embedded in the presentation.

For Microsoft Office PowerPoint 2003, for Microsoft PowerPoint 2002, and for Microsoft PowerPoint 2000

To work around this issue, reduce the default size setting for linked sound files before you add a sound file. To do this, follow these steps.

Note If you copy or move a presentation that uses linked sound files to another location, make sure that you also copy or move the linked sound files at the same time.

1. Start PowerPoint, and then open a presentation.
2. On the Tools menu, click Options.
3. Click the General tab, and then type a number that is smaller than the smallest sound file in the presentation in the Link sounds with file size greater than box. This number is now the default size setting for linked sound files.
   
   Note The smallest setting is 1 kilobyte (KB), and the largest setting is 50 megabytes (MB).
4. Click OK.
5. Insert a background sound file in the first slide in the presentation, and then configure the background sound file to play across multiple slides in the presentation.
6. Insert another slide, and then configure that slide to use built-in custom animation with sound effects.
7. Save the presentation.
8. Start the presentation.
9. Verify that the background sounds and the custom animation sound effects are played at the same time.
10. Close the presentation.