For the past couple days, once I've turned off my Magic Mouse and put the system to sleep as usual (via short touch of power button) over night, the system shuts down completely — with no log or error message indicating why. DU indicates that nothing has gone awry.
Is this an omen of impending iMac failure? Or what?
Running El Capitan 10.11.6 on mid-2011 iMac 2.5 GHz Intel Core i5.
