I was in the middle of doing an IOS update on my iMac when it turned off and now it does not finish the booting process. It starts and in the middle of the start up it shuts down.
iMac 27″, macOS 11.6
iMacs use Mac OS not IOS. However ,to help you what happens when you attempt to start up the iMac? If you don't hear or see anything that indicates a power issue such as a failed power supply. However if you see anything on the screen then it could be hardware or software. First thing to try is holding is unplugging it from power for 2-3 minutes then plug it back in and hold down the power button for about 15 seconds and see if it boots up.
My iMac was doing an update then in the middle of the upadate it shut off and now does not start
