原帖由： edvard.risheim ,
I have same problem at my A1418 21.5” Late 2012. The “fix” for me was to remove the PRAM battery, if i disconnect PRAM battery and insert it again it will work for one start up. If it goes long enough in sleep mode i have to redo the procedure. Therefore i have disconnected the PRAM battery entirely and works great for me. The next time i have to power it up i just have to unplug the charger cable for 5 sec(with PRAMremoved). I always leave the cable in the iMac until i have to start it and therefore i don’t have to set up date and time. I have no interess in trying to repair the issue as it works great as it is. I would recommend for you guys to try remove the PRAM and try to start it.