Mac waking up every 2 hours. Wake reason: EC.RTC (Alarm)

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Mac waking up every 2 hours. Wake reason: EC.RTC (Alarm)

My 2020 iMac with macOS Catalina keeps waking up every ~2 hours after I put it to sleep.

When I type

log show | grep -i "wake reason"

in Terminal, I get a log, where I can see the trigger for the wake up "Wake reason: EC.RTC (Alarm)"

After searching the internet I found many old threads with the same issue, but could not find any solution that would work or any guidance at all.

I found out that for me it was caused by a possibly faulty or corrupt system file which is in charge of scheduled Start up/wake and sleep.

I removed this file, then created new wake schedule, and then I reverted back to previous settings.

The steps I did are as follows:

Firstly, I would recommend to create a backup of your system
In Finder, go to /Library/Preferences/SystemConfiguration
Locate file com.apple.AutoWake.plist
Rename this file to com.apple.AutoWake.plist.ORIGINAL so you have a backup copy, just in case.
Navigate to System Preferences -> Energy Saver -> Schedule... -> Create new "Start up or wake" schedule
Click OK. This will create new com.apple.AutoWake.plist file
Go back to "Schedule..." and untick "Start up or wake"
Click OK
Done

This fixed the issue for me. I hope this will be helpful to other people with the same annoying problem!

iMac Line (2012 and Later)

Posted on Oct 14, 2020 1:29 AM

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kristian289 Author

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16 points

Oct 20, 2020 1:08 AM in response to kristian289

Update to my original post:

The fix mentioned above did not resolve the issue completely, however, I found another solution.

In Terminal, use pmset -g log | grep ' wake' to see scheduled events.

Run "pmset -g" to see system-wide power settings, and look for "tcpkeepalive".

If tcpkeepalive is "1", that's what is causing the computer to wake up every 2 hours, so I turned it off using command "sudo pmset -a tcpkeepalive 0".

This fixed my issue completely.

Note: tcpkeepalive is responsible for notification updates when the computer is sleeping. If you are using a laptop, you can choose to turn these notification updates off while the computer is sleeping and using power adapter only to preserve battery.

To do this, use command sudo pmset -b tcpkeepalive 0. If you want to turn this off completely, use command sudo pmset -b tcpkeepalive 0

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Mac waking up every 2 hours. Wake reason: EC.RTC (Alarm)

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