My 2013 iMac running Mojave 10.14.3 has had this problem for a number of years and spans a few OS upgrades. When in locked mode, the screen can stay lit indefinitely, until I hit Esc.

Behavior is like this. I lock my Mac, or just walk away from it until it locks itself up. I touch my touchpad or press any key to light up the screen. The screen will the stay lit - for ever. I have to manually hit escape to put it back to sleep.

My settings: I have screen saver on (10 minutes). In Power Savings, I have standard options. These are checked: Put hard disks to sleep Enable Power Naps

What can I do to fix this?

  • Any antivirus installed? I've known BitDefender not let Macs drop properly to 'screen off'. – Tetsujin Feb 17 at 16:14
  • No. I don’t run any anti-viruses on this Mac. I do run BackBlaze backup service. – Elijah Feb 17 at 16:25
  • kk. I've never known Backblaze to hurt anything, have it on a couple of machines here, so that wouldn't be in my suspect list – Tetsujin Feb 17 at 16:40
  • I currently have a similar issue, where my iMac doesn't sleep when it's in the login screen (username & password), unless you manually click on "sleep". – M.J.K Feb 17 at 20:07

I was able to temporarily correct this problem by deleting:


and restarting my computer.

This worked for a little bit, but stoped once I connected my iMac to my MBP as a Target Display.

  • Getting closer. Reset the System Management Controller (SMC), or in other words, shutting down and disconnecting from power, makes it go away until the next time I connect to Target Display. – Elijah Mar 8 at 4:10

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