Unwanted box in middle of home screen

Kizzme wrote:

My 16-inch 2020 MBP has a constant green box (about 3/4 inches square) in the middle of my home screen that I have been unable to get rid of. Would like to know how to remove it permanently.

It seems a screen shot would help in trying to narrow this down...

Is this something you have enabled in Accessibility(?)

>System Preferences>Accessibility

To trouble shoot further you can:

—Try a SafeBoot How to use safe mode on your Mac - Apple Support

Takes noticeable longer to get to the login screen, does a 5 minute disk repair before it fully boots up, and certain system caches get cleared and rebuilt, including dynamic loader cache, etc.

Login and test. Reboot as normal and test. Caches get rebuilt automatically.

In Safe mode third party system modifications and system accelerations are disabled, it removes malware, etc hampering smooth operation, however a reboot will put it back to normal mode.

This test will tell you if third party interference; extensions etc are not loaded in safe boot mode.

—Test issue in another user (or guest user) account Set up users, guests, and groups on Mac - Apple Support

This will tell you if it a universal issue or isolated to your user/admin account. 

Uninstall all third party apps that are Cleaners/Optimizers/VPN/Anti-Virus

all known to cause issues on the macOS

Kizzme wrote:

https://discussions.apple.com/content/attachment/610928e6-c913-4cd4-94b2-771fc9fa9785

And what did you discover in SafeBoot and a guest user same issue...?

what is this app?