Tonight I followed the instructions someone had posted to this forum (and lots of other places online) to run the following in Terminal: sudo defaults write /System/Library/LaunchDaemons/com.apple.backupd-auto StartInterval -int 86400 Then I logged out and then logged back in again to reload. This is supposed to change the Time Machine backup interval from 1 hour to once every 24 hours. Maybe it does, but I noticed something weird: every time I load up Time Machine Preferences from the menu bar, the time to "Next Backup" changes by subtracting 1 hour or so from its previous value just a few minutes ago when I checked. If I check again immediately, it is the same (e.g. Today, 9:20pm) but if I wait awhile and load it again, it changes to something like "Today, 8:20pm" Not sure what's going on here and can anyone offer any comments if I even executed this command correctly in the first place?