Unable to save Illustrator file and quit the app

Hello @NIxel26528590k7,

Sorry to hear about this experience. Would you mind trying to reset Illustrator's preferences by following the steps shared in this article (https://helpx.adobe.com/illustrator/kb/troubleshoot-preference-issues.html) and sharing your observations?
Disclaimer: Please note that resetting preferences will remove all custom settings, and Illustrator will launch with the defaults. You may take a backup of these settings from the location mentioned in the article.

If the issue persists, kindly share the exact version of the OS and Illustrator installed on your computer and a screen recording of the problem so we can investigate this further.

Looking forward to hearing from you.

Thanks,
Anubhav

Also: which version and system is it?

It would really help if you could give us a step by step description.

What have you already done to try to resolve the problem? Pointless telling you things you've tried...

(btw, nothing attached to your post)