Why can't I convert a file created in Presentations 8 with v.10 modifications to a PowerPoint slide show?

Why can't I convert a file created in Presentations 8 with v.10 modifications to a PowerPoint slide show?

This is a bug in Presentations 10. Since the goal of converting the slide show to PowerPoint was so that students could take the file for review or printing of individual slides, it is suggested that the file be converted to .pdf format.