It is not usual question on Illustrator

TakaiMura

I'm using Adobe Illustrator CC 2017.0.2. Many times I had some issues. Couple of days ago .ai file didn't opened. I checked other files, they were fine. How to be with that file?

Axi5

Ai files, like many other files, can be corrupted. Sorry for your lost work. There's a website I know that tries to fix AI files, it didn't work for me in my particular case though. I can't even remember if the AI files are binary or not.

HamanSorkhab

Then you can't open .ai file via any method apply more powerful solutions as how to repair illustrator file

 

This one blog is very interesting, it is related your issue - http://smallbusiness.chron.com/recover-work-illustrator-39270.html

 

It is the source of guide below: https://helpx.adobe.com/illustrator/kb/troubleshoot-damaged-illustrator-files.html

 

Place the damaged Illustrator file in a new Illustrator file.

Important: This solution doesn't work if you didn't select Create Compatible PDF File in the Illustrator Native Format Options dialog box when you saved the original file. On the Macintosh platform, the damaged Illustrator file may appear dimmed in the Place dialog box, but you will still be able to select it and place it in the new Illustrator file.

1. In Illustrator, choose File > New.

2. Select the appropriate size and color mode, and then click OK.

3. Choose File > Place.

4. In the Place dialog box, choose All Formats from the Files of Type pop-up menu (Windows) or choose All Documents from the Show pop-up menu (Mac OS), choose the damaged file, and then click Place.

5. Name and save the file.