The spinning rainbow wheel will appear on your computer's screen when macOS detects that your system can't keep up with all of the tasks you're asking it to handle.

To stop the spinning wheel on Mac, Force Quit the application that's causing it or force restart your computer. You can also stop the spinning wheel by closing background apps you're not using.

The spinning rainbow wheel will appear on your computer's screen when macOS detects that your system can't keep up with all of the tasks you're asking it to handle.