Adjust Time Machine backup frequency

I managed to get a oldish 3Tb Time Capsule off Carousell for experimenting. It was pretty alright for the first day until I got tired of the hourly loudish HDD spin up.

There must be a way to adjust the hourly backup frequency to every 6 hours. Given this is a oldish EOLed device, I also want to preserve its longevity – as much as i can.

To do so, determine the new backup frequency you want it to be, knowing the backup daemon reads in the backup frequency in seconds.

If you want to adjust to a 12 hour backup, the new number would be 60 seconds * 60 minutes * 12 hours = 43,200

For a 6 hour backup frequency, the new number would be 60 seconds * 60 minutes * 6 hours = 21,600


  1. Go to the macOS terminal app and do the following:
  2. Unload the backup daemon using “sudo launchctl unload /System/Library/LaunchDaemons/
  3. Change frequency on the the following file /System/Library/LaunchDaemons/ using “sudo nano /System/Library/LaunchDaemons/
  4. Look for the line that says “<key>Interval</key><integer>3600</integer>“, change the integer value to the newly calculated value above without the comma.
  5. It should read the following with a 12 hour backup frequency “<key>Interval</key><integer>43200</integer>
  6. Save the file with Ctrl-X.
  7. Then reload the plist using “sudo launchctl load /System/Library/LaunchDaemons/

You will only hear the HDD storage startup only twice a day, and extend the HDD’s life!

PS – The above was verified to work on Mojave.

PPS – You will need to do this for every macOS device.

2 thoughts on “Adjust Time Machine backup frequency”

  1. In Catalina (and above) /System/Library/LaunchDaemons/… is a “read-only” filesystem. sudo chmod is no longer allowed. A copy of is also not available at /Library/LaunchAgents.

    Does anyone know how to get around this without using another OS to access the file?

    1. Interesting. Have you tried getting into Single User Mode (on power up, hold down Cmd + S) and adjust the file?

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