When you have a backup drive connected to your Mac, you may want to eject it before disconnecting it. This ensures that the drive is properly disconnected and that your Mac doesn’t try to write to it anymore.
To eject a backup drive on a Mac, open a Finder window and select the drive from the sidebar. Then click the Eject button in the toolbar.
If the drive is already disconnected, you can eject it by opening the Terminal app …
