To link your new computer's disk to your Time Machine drive, follow these steps: How to associate your computer with a Time Machine? Also, because the new MacBook Pro didn't recognize the previous Time Machine drive, we couldn't retrieve backups from before the transfer. Because the initial Time Machine backup drive was less than half full, this was a bit of a waste. I'm not sure why, but we needed to purchase a new external hard drive for a new Time Machine backup. We were unable to set up Time Machine on the new MacBook Pro using the previous Time Machine disk since everything transferred successfully. To load everything onto our then-new(ish) MacBook Pro, we utilized Migration Assistant and a Time Machine backup. But it should work, and formatting the drive will very probably prevent you from accessing your previous backups. It's possible that anything goes wrong during the association procedure, causing you to lose all of your prior backups. You may link your new internal drive to Time Machine, letting it continue backing up your data. Of course, this implies that all of your previous backups are gone. After you restore, you may format the Time Machine disk and configure it as the Time Machine destination as usual. (It's attempting to prevent the backup of another disk with the same name from interfering with existing Time Machine backups.) However, because the identity of the internal drive on your new computer does not match the identifier of the internal drive on your old computer, Time Machine will not back up your new computer to that external drive. You may restore your backup to your new Mac using Migration Assistant and your Time Machine external disk when you get a new Mac.

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