I have a MacBook Air, and use a dongle with a few drives on it. I realized NOTHING on the external drives is being backed up, just the system disk on the MBA. There seems to be no apparent way to tell Time Machine what to back up, you can only exclude system files. This is insanity, this can't be right, please someone tell me what I need to do to back up ALL of my Mac's drives to a back up source.
MacBook Air
If you have no drives excluded, then your external drives are backing up to your Time Machine drive. You can check by opening your Time Machine drive and expanding the view on any selected backup as below:
There are no drives excluded. I can chose the external drives to be backed up TO, as a destination, but not as a source. Ditto for my networked files on other computers, I can't select those either to be backed up.
Just to elaborate, open System Preferences > Time Machine > Options…
Remove any drives in the list you don't want excluded.
If you have an external drive connected to your Mac, it will backup to your Time Machine drive unless you exclude it.
I'm using a MacBook Air, and that is not how it works. Sorry.
How do you back up an external drive using time machine?
