Engage slide not inserting into project

Hi,

I built an engage slide that comes up in the list when I select the engage button to insert it into the presentation. However when I say open I get a message saying that the slide is already in the project would I like to update it. 

First the slide isn't in the project and when I tell it to update it, it still doesn't put it in the slide presentation. 

Any ideas why this is happening and how to get it to put the engage slide in. It was a lot of work to get it just right and I really don't want to have to do it all over again.

Thanks,