Mike Keslosky uses Time Machine and wants to move his photos and iTunes libraries from his boot volume to an externally connected hard drive. But he worries that after he moves and deletes those libraries from his internal drive, Time Machine won’t back them up.
Fortunately, Time Machine can back up any locally attached drive, though Apple configures it to exclude external drives by default. If you have a Mac Pro or other system that you’ve partitioned or configured with multiple internal drives, they’re all included by default.
You can ensure that external drives are backed up by following these steps:
- Open the Time Machine system preference pane.
- Click the Options button.
- Select a disk from the exclusion list that you want Time Machine to have Involving.
- Click the – (minus) button to remove it. (Repeat for additional stations.)
- Click Save.
That’s all you need to do.
The list of exclusions is confusing as you may only want to include certain parts of an external drive. There is no built-in way to enable this. Let’s say you want to back up a Movies folder on an external drive, but none of the other five top-level folders. You need to add each of those other top-level folders to the Exclude list by clicking the + sign and then selecting them one by one.
If you want help using Time Machine to back up your Mac, read: How to use Time Machine to back up a Mac. We also have How to back up your Mac, a roundup of the best backup software for Mac and the best cloud storage services for Mac.
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