> iMac keeps falling asleep
My iMac keeps falling asleep unexpectedly, although it always wakes up reliably. What’s wrong with it?
Sleep and wake are functions controlled by the System Management Controller (SMC) and a complex series of settings, some of which are exposed in the Energy Saver pane. Your first step is to reset the SMC following the instructions relevant to its type, at bit.ly/mac361nvram. In the case of desktop Macs without a T2 chip, that means shutting it down, disconnecting all peripherals apart from keyboard, mouse/ trackpad, any Ethernet connection, and any external display. Disconnect the power cable for at least 15 seconds, reconnect it, wait a further five seconds, and start up normally.
Once your iMac is running, carefully review the settings in the Energy Saver pane. Also worth a visit is the Screen Saver tab in the Desktop & Screen Saver pane, where you should ensure that you disable sleep from any of the
Hot Corners, just in case they’re getting activated inadvertently. If that doesn’t keep your Mac awake, suspect its hardware, so run Diagnostics. You might consider getting a store to run their advanced diagnostics if that doesn’t show anything.
As a workaround, you should find Amphetamine
(free) or Caffeinated, from the App Store — these apps are helpful for keeping your Mac more awake.