I find that whenever I switch on mains power to my iMac, it turns itself on automatically after about 10 seconds. Before I always had to turn on using the iMac power button at rear. Can I change this to manual operation as before? I am running Ventura OS 13.2.1 on a 2019 Intel iMac. I emphasise that this happens when I switch mains power on, not when Mac is asleep.
iMac
The startup issue is happening, because you are turning off the power to the iMac.
If the external drives do not sleep with the iMac, then you need to Eject and disconnect them or replace them with ones that do.
A work-around might be to use two power strips.
connect the iMac and other devices to one power strip and leave it on.
connecting the external drives to the other power strip, then eject the external drives and turn off that power strip before sleeping or shutting down the iMac.
The startup issue is happening, because you are turning off the power to the iMac.
If the external drives do not sleep with the iMac, then you need to Eject and disconnect them or replace them with ones that do.
A work-around might be to use two power strips.
connect the iMac and other devices to one power strip and leave it on.
connecting the external drives to the other power strip, then eject the external drives and turn off that power strip before sleeping or shutting down the iMac.
You might give this power manager a look at: Tripp Lite Under-Monitor 6-Outlet Surge Suppressor
You can have it control all peripherals and have the computer powered all the time so it can be powered up with the external drives if needed. I have 4 external SSDs, and optical drive and my iMac controlled by one.
Go to Apple > System Settings > Energy Saver > turn "Start up automatically after a power failure" Off.
I need to switch off this power supply as it feeds other devices (external drives) and I don't want them running overnight. Also this start up issue does not happen when the iMac is temporarily put to sleep.
Yes thanks already done that.
Why are you turning off the main power to the iMac?
If you leave the main power on and shutdown using the Apple menu, then you will need to push the power button to turn the iMac back on.
Thank you, very helpful. I shall now consider my options and alternatives.
iMac turning on automatically. How do I stop?
