Why doesn't the title show in my iMovie slide show after editing?

If you have confirmed that you are following the correct procedure for title insertion, and still no luck, then try deleting preferences.

To delete preferences, open iMovie while holding down the Option and Command keys and select to delete preferences in the box that appears. iMovie will open in a new empty library. Reopen your old library to get back to your projects. Now see if you can add titles. Possibly you may need to reboot to set the changes.  Deleting preferences is a safe procedure that will not cause data loss or disruption to your project.

-- Rich

Hi,

First double check that you are following the correct procedures for adding a title. See the following help link.

https://help.apple.com/imovie/mac/10.1/

— Rich