Are there any recent changes made to your system? For example, any antivirus, system updates, plugins, or web extensions installed recently.
A small video demonstrating the issue could be really helpful.
Does resetting Illustrator Preferences ( https://helpx.adobe.com/illustrator/using/setting-preferences.html) help to resolve the issue? 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.