Thanks for reporting this issue, Illustrator team really appreciate this.
Unfortunately we are unable to reproduce this issue in house, Kindly help Illustrator Team to nail this issue down further:
Kindly provide the exact preferences you are using and the data from below mentioned location .
Mac:- /Users//Library/Preferences/Adobe Illustrator 2X Settings
Win:-C:\Users\\AppData\Roaming\Adobe\Adobe Illustrator 2X Settings
Share the above information with us at ShareWithAI@adobe.com in a Zip file. Please mention the title of this issue as the subject of the mail.
Thanks and Regards
An error occurred while saving the commentwaqar malik commented
it works fine but if i turn off my Laptop then turn it on and start illustrator then its settings are rest completely.