I just ran into a loop I don't know how to get out of.

I've been saving my work by clicking on the "floppy disk" at the top
of the screen. The last time I did so, I decided to check the box that
says something like "Don't show this dialogue box again."

But now I WANT to see the dialogue box so I can save an OPML file to
my hard disk.

But I don't know how to get it back ?

Help ! Thanks :)