Time Machine, the automated backup utility built into Mac OS X, is set to run every hour by default. Is this too often for you? Find out how you can change the backup interval, plus how to initiate backups only when you trigger them manually.
For most people, hourly backups with Time Machine are just right for keeping their Mac’s precious files safe from disaster. But, as with all things related to technology, everyone has their own personal preferences and needs. That means automatically backing up every hour is overkill for some folks and simply not often enough for others. Terminal to the rescue! A quick command lets you to set a custom interval of your choice.
Set Time Machine’s backup interval
Since the preference file Time Machine uses to schedule automatic backups handles time in seconds, the default 1 hour interval is represented by 3600. That is, 60 seconds x 60 minutes. When you enter your own value to replace 3600, make sure it is in seconds. There’s really no limit to how high you can make this number – 7200 for 2 hours or 14400 for 4 hours are good ones. For the sake of saving system resources and avoiding conflicts, I wouldn’t go any lower than 1800 for 30 minutes. With that said, let’s figure out how to do this.
Open Terminal (Applications > Utilities) and copy & paste the following command (all one line). Replace 3600 with your chosen time interval in seconds.
sudo defaults write /System/Library/LaunchDaemons/com.apple.backupd-auto StartInterval -int 3600
Press Enter/Return to run the command. A password prompt will appear in Terminal. Type your administrator password, but be aware that the cursor will not move. It is registering your keystrokes, though, so don’t be alarmed. Press Enter again and you’re all set. While I don’t know if this is necessary, restarting your Mac would be a good idea at this point to make sure the changes go into effect.
UPDATE – 4/7/12: This method no longer works in OS X 10.7 Lion. However, there’s a free program called TimeMachineEditor that does the same thing and works with Lion.
Only backup with Time Machine manually
For those of you who like Time Machine’s simplicity and ease of use but don’t like the idea of automated backups, you can enjoy the best of both worlds. Simply go to Time Machine in System Preferences and move the big switch to Off. This disables all scheduled backups and only needs to be done once.
Now go to the Desktop or Finder and right-click on your Time Machine backup drive. Select “Back Up Now” from the menu and a manual backup will start. Follow this two-step procedure every time you want to do a backup.