iMac won't sleep automatically since macOS Catalina

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Level 1

14 points

iMac won't sleep automatically since macOS Catalina

Since updating to macOS Catalina, my iMac will not sleep automatically correctly.

When Power Nap is enabled, it will go to sleep after the period set in System Preferences/Energy Saver. It then wakes almost immediately for roughly a minute, then sleeps. It then fails to sleep after the first time it wakes to do its backup/sync tasks.

When Power Nap is disabled, it simply fails to sleep automatically at all.

It will sleep properly and seemingly indefinitely if I put it to sleep manually via keyboard shortcuts or the apple menu.

I have tried everything I can think of or have found suggested in online searches or in Apple's help pages, even to the extent of a clean reinstall of macOS Catalina 10.15.3. With no data restored or non native software installed, no external peripherals connected other than Ethernet, it behaves exactly the same way, which suggests this is not being caused by software I have installed, or external hardware (USB 3 HD and Audio/MIDI interface). It just will not sleep automatically.

This machine and exact configuration worked just fine under macOS Mojave.

For reference,

iMac Retina 5K, 27-inch, Late 2015)

Processor 3.2 GHz Quad Core Intel Core i5

Memory 32GB 1867 MHz DDR3

Startup Disk Macintosh HD

Graphics AMD Radeon R9 M390 2GB

I have 764GB available of the original 1.02TB Fusion drive available, the hardware is all as supplied and all software is currently up to date.

Anyone have any idea what's going on? It's not the end of the world but I prefer not to power down manually and would rather it sleeps automatically when idle. I have found a couple of threads from others online with similar issues but nothing anyone has suggested so far has made any difference.

Many thanks!

iMac 27", macOS 10.15

Posted on Feb 5, 2020 10:20 AM

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Answer 1

Kappy

Level 10

361,741 points

Feb 5, 2020 9:14 PM in response to dieselfish

A Troubleshooting Procedure that may Fix Problems with macOS El Capitan or Later

You should try each, one at a time, then test to see if the problem is fixed before going on to the next.

Be sure to backup your files before proceeding if possible.

Shutdown the computer, wait 30 seconds, restart the computer.
Disconnect all third-party peripherals.
Resetting your Mac's PRAM and NVRAM
Reset the System Management Controller (SMC)
Reset your Startup Disk and Sound preferences, if needed, after resetting the PRAM.
Test in safe mode to see if the problem persists, then restart normally. Use safe mode to isolate issues with your Mac and Playing Safe - what does Safe mode do?
Repair the disk by booting from the Recovery HD. Immediately after the chime hold down the Command and R keys until the Utility Menu appears. Choose Disk Utility and click on the Continue button. Select the indented (usually, Macintosh HD) volume entry from the side list. Click on the First Aid button in the toolbar. Wait for the Done button to appear. Quit Disk Utility and return to the Utility Menu. Restart the computer from the Apple Menu.
Repair permissions on the Home folder: Resolve issues caused by changing the permissions of items in your home folder.
Create a New User Account Open Users & Groups preferences. Click on the lock icon and enter your Admin password when prompted. On the left under Current User click on the Add [+] button under Login Options. Setup a new Admin user account. Upon completion log out of your current account then log into the new account. If your problems cease, then consider switching to the new account and transferring your files to it - Transferring files from one User Account to another.
Download and Install the macOS Catalina 10.15.3 Combo Update.
Reinstall OS X by booting from the Recovery HD using the Command and R keys. When the Utility Menu appears select Install OS X then click on the Continue button.
Erase and Install OS X Restart the computer. Immediately after the chime hold down the Command and R keys until the Apple logo appears. When the Utility Menu appears:

1. Select Disk Utility from the Utility Menu and click on the Continue button.

2. When Disk Utility loads select the drive (out-dented entry) from the Device list.

3. Click on the Erase button in Disk Utility's toolbar. A panel will drop down.

4. Set the Format type to APFS (for SSDs only) or Mac OS Extended (Journaled.)

5. Click on the Apply button, then wait for the Done button to activate and click on it.

6. Quit Disk Utility and return to the Utility Menu.

7. Select Install OS X and click on the Continue button.

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Answer 2

gjdkeu

Level 1

75 points

Feb 6, 2020 6:27 AM in response to macjack

Read more here: https://discussions.apple.com/thread/250933408

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Answer 3

macjack

Level 10

111,168 points

Feb 6, 2020 5:50 AM in response to dieselfish

FWIW, I gave up on the Sleep function years ago. Ever since the inception of OS X there have been Sleep related issues. And even more lately. I just use Display Sleep and keep it set for 15 minutes so I'm not burning the screen. No put hard disks to sleep (they should spin down on their own after about 10 minutes of inactivity), no wake for network access.That way your Mac uses very little power over Sleep and is ready to use at the touch of a key without any grogginess. UNIX based systems were made to be always on and they’ve been running busy servers 24/7 for decades.

My own 2010 iMac has been used daily and has never slept a day in its life. It's still going strong.

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