I still run into folks that see that issue and learn about some font that was on the original machine but not the new machine. At first they call it "corrupt."
I'm having trouble with an rtf made from a Word file (extended latin characters get corrupted). Can't find anything strange about the Word file except the extension is ".DOC" (caps). Is that indicative of the file being made by an older version of Word or originating in a different application?