I spend so much goddarmn money on Adobe software and it is such a constant disappointment. Shieit that's been working for a decade suddenly just stops working and faoucks up your whole workflow. Focus less on adding the 900th Adobe application and maybe get the ones that9 already exist to work right. Fouckk monopolies. Fouckk Adobe
If you don't give us actual pointers to what the issue is how can we help..? We are all just people like you here in the forum and help people out of kindness, nobody will help if you speak like this...?
Disclaimer: Please note that resetting preferences will remove all the custom settings, and Illustrator will launch with default settings. You can also take a backup of the folders in case you want to. Location is mentioned in the article.