Time Machine not backing up
I have an iMac using the latest OS, I have Time Machine set to automatically back up, but every morning, I have to tell it to Back Up Now to get it started for the day. WHY?
iMac (2017 – 2020)
Question marked as
Have you set Time Machine's "Back up frequency" to Daily? If so, that simply means that TM will do a back up at some point during a 24 hour period but not necessarily at the beginning of each day.
To set the back up frequency go to System Settings > Time Machine and click the Options... button.
It's very likely that if you simply allow TM to do its thing unattended, it will back up at some time during the day.
If you still find that is not happening, change the frequency to "Automatically Every Hour". Time Machine will back up the Mac in the background without intervention and without interrupting your work whether hourly, daily or weekly.
If you discover that TM is not backing up at all, the best usual fix is to start a fresh back up set with a newly reformatted external drive.
Please see: Use Time Machine to back up - Apple Support