Unwanted black box appeared on Illustrator 2019

Hi!

I need help solving the problem of this unidentified black box that shows up whenever I am in Illustrator 2019. I have been using Illustrator 2018 for awhile until this last update, which now the 2018 version is disappeared off my computer. Can someone help me get rid of this black box.

I have tried escape key, rebooting, updating...I can't click on it (nothing happens when I do) or highlighting it.

Thanks for anyone's help.

{Renamed by MOD}