Blue Box appears while scrolling up on the Illustrator screen on macOS Mojave

Thank you to Mylenium AND Bill Silbert!!! After I turned off GPU Acceleration as Mylenium suggested, the Blue Box disappeared! But my computer's performance suffered. Everything in Illustrator slowed down. So I followed Bill's advice and trashed my Illustrator preferences, and now everything is back to normal. Thank you both VERY much!!

Hi Lauren,

Thanks for reaching out. I see the blue box on the screen. I am hopeful that the suggestions shared above worked for you. If not, please share the following details:

• 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 booting the system in Safe Mode (Start in Safe Boot mode for Adobe products on Mac OS X ) helps?
• If not, please go to System Preferences > Energy Saver and Uncheck the box next to “Automatic graphics switching” and let us know if this helps.

Looking forward to your response!

Regards,

Srishti

Have you installed any OS apps that modify the background or known  trojan horse software like cleanmymac?

Try changing the highlight color, to something else beside default blue, to test if coming from that. Dark mode is problemtaic, get out of that if your are in.

In addition to Mylenium's advice, you should also try trashing your Illustrator preferences and see if the program works correctly when it has been set back to defaults. Even if the problem persists that would at least eliminate the program itself as the culprit and attention could then be focussed on a hardware problem.

To trash preferences on a Mac:

The User Library folder in which Illustrator’s preferences are stored is hidden by default on most Macintoshes. To access it make sure that Illustrator is closed and click on the desktop to launch a Finder Window (Command-N).With this window in column view follow the path User>Home folder (it’s the folder with an icon that looks like a house—it may have the user’s name rather than “Home”) and click on the Home folder. With the Option Key pressed choose Library from the Finder Go Menu. “Library” will now appear within the Home folder. Within the Library folder find the folder called Preferences and within it find the folder called “Adobe Illustrator <Version #> Settings” (earlier versions of Illustrator might just say “Adobe Illustrator”) and the file called “com.adobe.Illustrator.plist” and delete both that folder and that file. When Illustrator is next launched it will create new preference files and the program will be restored to its defaults.

The advantage of manually deleting preference files in this manner is that after you’ve reset up the program (make sure that no document window is open) to your liking, you can create copies of your personalized “mint” preference files (make sure that you quit the program before copying them—that finalizes your customization) and use them in the future to replace any corrupt versions you may need to delete.