aiデータを復元させたい！！

おだいじに、

私は友達にこれを日本のフォーラムに移動させるよう頼んだ、

https://community.adobe.com/t5/illustrator%E3%83%95%E3%82%A9%E3%83%BC%E3%83%A9%E3%83%A0/BD-P / ILLUSTRATOR - JP？PAGE = 1＆SORT = LETTED_REPLIES＆FILTER = ALL

An AI file contains a PDF inside of it as private data (when you save with "PDF compatibility" turned on)

So the PDF content is a separate thing and the AI part is as well.

What you can do: make a copy of the file (important).

Then open one of the copies.

Then create a new file.

Place the other copy into it (uncheck "linked")

Copy those parts from this new file that are missing in the file you opened. and paste them into it.

That way you get the best of both worlds.

If you want to be really safe: Create another new file and copy all the content into it. Then save it.

Now to the reasons that this might happen.

Don't save directly over  a network or on USB drives

Turn off "Save in Background" in the preferences.

Check your harddrive for corruption in case this happens often.