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.
>File, Save.
>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!
More various resources that I found from Google and Yahoo
https://helpx.adobe.com/illustrator/using/crash-file-data-recovery.html
https://download.cnet.com/Recuva/3000-2242_4-10753287.html
https://onlinefile.repair/en/illustrator.html
This has worked when nothing else has… believe me it is painful to have to recreate a corrupt file….
It much better to make what you like and what you know as yourself