Illustrator windows open in half/ small sized window instead of Full screen on macOS

Hi there,

Sorry about the trouble. By default, Illustrator opens the full screen in macOS and retains the previous size of the window. So, if you resize the Illustrator window to half and close it, then next time, it will open in half. Similarly, if you resize the Illustrator window to full screen and then close it, Illustrator will open in Fullscreen next time. If it is not happening like this, then I would request you to share a few more details along with the ones asked by @Simmer1:

• OS and version of Illustrator
• When did this start happening? Are there any recent changes made to your system? For example, any antivirus, system updates, or web extensions installed recently.
• Does resetting Illustrator Preferences (https://helpx.adobe.com/in/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.

Thanks & Regards,

Anshul Saini