
You can check to be sure everything was cleaned up by visiting System Preferences again the red icon at the bottom should be gone. My computer is a pretty fast 2018 MacBook Pro, and I waited several minutes with a spinning beach ball before the uninstaller was all done.

Seriously, the process to uninstall Flash takes a surprising amount of time. Also note that the process can take quite a while depending on your system configuration and speed. Note that you can’t have any apps open that are currently using Flash, so be sure to quit those apps if you receive a warning. If you have multiple versions of the Flash Player installed, the uninstaller will run multiple times to get them all.

Inside, find and double-click on Adobe Flash Player Uninstaller.app to launch the Flash uninstaller.

An easy way to tell is to click on the Apple Menu at the upper-left corner of your screen, choose System Preferences, and then look for the red Flash Player option at the bottom.
