Turned off bluetooth now can't use the mouse iMac OSX

From Cookipedia

If you turn Bluetooth off you might not be able to control the computer.
For example, you won't be able to use a Bluetooth keyboard or mouse. Are you sure you want to turn Bluetooth off?

On an iMac, if the ignore the messages above and still switch Bluetooth off, you'll find you have no way to control the computer (and turn Bluetooth back on) unless you have a corded mouse.

The following steps will be the solution to your problem.

  1. Stop swearing.
  2. Perform a forced shutdown by holding down the power button.
  3. Wait 10 seconds (switching equipment on and off instantly is never a good idea).
  4. Momentarily press the power switch to switch the PC back on.

  1. After 10 seconds the logon screen should appear.
  2. Wait another 30 seconds and the Bluetooth Login Assistant screen message should appear.
  3. Bluetooth has been automatically re-enabled.
  4. Problem solved. Bluetooth has been switched back on and Your keyboard and mouse (or trackpad) have been re-connected.
Next time, heed the warnings!

See also