Time Machine External Backup Disk Question

I have a MacBook Pro.

If an external backup disk is ejected before completing the backup, does it remember its place or do I have to start from scratch?

It's telling me that the backup will take 4 days.

Thanks

MacBook Pro 13″

Posted on Mar 26, 2025 8:19 AM

Reply
Question marked as Top-ranking reply

Posted on Mar 26, 2025 9:56 AM

Backups take place on an ongoing basis when the computer is awake and not too busy. if you Sleep, Shutdown, or Restart your computer, or Eject the drive to take the computer to work or school, the backup simply continues where it left off when re-connected and awake.


if you disconnect the drive without properly ejecting it first, you MAY have to run Disk Utility and Repair/FirstAid the Drive directory before it can be Mounted again to proceed.


Those estimates run very high, especially the original estimate for the first Full Backup. As the backup proceeds, the estimated time remaining becomes more accurate. Your second and subsequent backups are incremental backups, and are MUCH quicker.

1 reply
Question marked as Top-ranking reply

Mar 26, 2025 9:56 AM in response to Winemusic

Backups take place on an ongoing basis when the computer is awake and not too busy. if you Sleep, Shutdown, or Restart your computer, or Eject the drive to take the computer to work or school, the backup simply continues where it left off when re-connected and awake.


if you disconnect the drive without properly ejecting it first, you MAY have to run Disk Utility and Repair/FirstAid the Drive directory before it can be Mounted again to proceed.


Those estimates run very high, especially the original estimate for the first Full Backup. As the backup proceeds, the estimated time remaining becomes more accurate. Your second and subsequent backups are incremental backups, and are MUCH quicker.

This thread has been closed by the system or the community team. You may vote for any posts you find helpful, or search the Community for additional answers.

Time Machine External Backup Disk Question

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.