When I open certain files I get a missing font message (despite the fact that no fonts have been deleted from my system) and InDesign has randomly replaced a font which I have used in the document with one I don't have. Why? And how do I find out what the original font was?
In the Type menu, choose Find Font. It will bring up a dialog box that lists all the fonts used in your document, with a yellow caution triangle next to the ones that are missing.