How to Fix Random Sleep Wake and Screen Activity on iMac 2017

How to Solve Sleep Disturbances and Unwanted Wake Events on iMac 2017

iMac 2017 models running macOS Sequoia via OpenCore Legacy Patcher can sometimes suffer from random sleep disturbances where the screen turns on at night or the system fails to remain asleep. This behaviour is caused by network wake requests and power management settings.

1. Prerequisites

• Target Hardware: iMac 2017 (iMac18,2 or iMac18,3) running macOS Sequoia.
• Required Tools: macOS Terminal.

2. Compatibility Snapshot

• Sleep State Support: Native sleep is supported, but modern macOS versions enable active background services (like Power Nap) that trigger wake states.

3. Installation Preparation

1. Check Wake History: Open Terminal and execute pmset -g log | grep -i "wake reason" to identify which device or service is waking the iMac.

4. EFI and config.plist Review

1. This does not apply to this case as sleep state variables are managed by the macOS system configurations.

5. Post-Installation

1. Disable Network Wake: In Terminal, disable proximity wake and network keepalive requests: sudo pmset -a proximitywake 0 tcpkeepalive 0 womp 0 powernap 0.
2. Disable Bluetooth Wake: If the wake reason is listed as Bluetooth, go to System Settings -> Bluetooth -> Advanced and disable "Allow Bluetooth devices to wake this computer".

6. Troubleshooting

Reported Issue: iMac screen turns on randomly

1. Prevent Maintenance Wake: Some wake events are scheduled by the system for maintenance. Set autopoweroff to 0 using: sudo pmset -a autopoweroff 0.

7. Dual Boot and Advanced Configuration

• This does not apply to this case because sleep management is OS-specific.

8. Verification, Maintenance and Rollback

• Verify Fix: Put the iMac to sleep and confirm it remains asleep for several hours without the display turning on.

9. References and Glossary

• womp: Wake on Magic Packet (Wake on LAN).
• Power Nap: A feature that allows the Mac to perform updates and syncs while asleep.