I have one of the maxed out iMacs with 3TB fusion drive. For the last two mornings it hasn't booted up. Yesterday it had to be booted up in safe mode to start and this morning I simply restarted it and the second time it worked. It goes to either a plain white screen or it shows a circle with a line through it with the continuous "waiting to load" circle. I have bose speakers connected (turned off), an ethernet cable and my apple phone charger plugged into it. Don't know why this would make a difference but maybe so... Anyone else having a problem?