How to make sure Time Machine backs up external drives

By default, Time Machine does not back up external drives, but you can change this.

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Apple

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Glenn Fleishman is the author of dozens of books. His most recent include Take Control of Your M-Series Mac, Take Control of Securing Your Mac, Take Control of Zoom, and Six Centuries of Type and Printing. In his spare time, he makes Tiny Type Museums. He’s a senior contributor to Macworld, where he writes Mac 911.