Comments display in my slide show.
If you don't want to delete your comments, you can hide them so they don't appear in a show. To do so, click the Show/Hide Comments button on the Reviewing toolbar.
I thought I copied slides from one presentation to another, but now they've disappeared from my original presentation.
Be sure to use Ctrl+C (copy) rather than Ctrl+X (cut) if you want to keep the original slides in place. Moving slides removes them from their original location; copying just creates duplicates.