< Open the AI file you want to repair.
< Choose "Object" and then choose "Path."
< Choose "Cleanup." (Note: Empty text paths, stray points and unpainted objects will be deleted.)
< Choose "Paste Remembers Layers" only if your AI file contains multiple layers. (Note: This option is available from the Layers Panel menu.)
< Drag a marquee around all of your artwork in the file by using the Selection tool.
< Choose "Edit," "Copy," and then choose "File."
< Choose "New," "Edit," and then choose "Paste in Front." (Note: "Paste in Front" will place your artwork will mirror the damaged AI files).
< Choose "File" and then choose "Save." If your file is still damaged, continue.
< Make a copy of the file and give it the same name except add the "C1" to the end of the title. (Note: You can choose any other letter, number or other word to differentiate it from other versions.)
< Open the first copy version, select one art object within the file, and then delete it.
< Save the file and add a number "C2" at the end of title to differentiate it from other copies and then reopen the file. If your file is still damaged, continue.
< Repeat steps 10 and 11 until you can identify the object that is causing the problem.
< Delete the damaged object when you find it and then re-create it by using either the drawing tools, reestablishing a link, or by changing or replacing the font of damaged text.
Also see more info on this Microsoft site: Edit [Moderator]: Link removed