I’ve experienced this problem many many times and just accidentally found the solution today, DOH!!!!! :). Thanks to Yael Miller from thedieline.com for the usefull tips. Tips after the jump.
This will work in Adobe Illustrator 10 and up (but try it in older versions – it may also work.)
Requires Acrobat (not just the Reader).
Works on (and was tested in) Illustrator version 10 and all CS versions.
>Open the corrupt file in Acrobat.
>Take the arrow tool.
>Click on any element or text in the document.
>Just move the object by hitting one of the directional arrows on your keyboard.
>Open the file in Illustrator.
>It will say ‘this file has been modified outside of Illustrator’ or something to that effect. it will ask if you want to keep changes.
>Say ‘Yes’ (or OK)
Your file will open virtually intact!