How to fix a Mac Time Machine failed backup

What to do when Time Machine backups fail on the Apple Mac. Don't panic, help is here. Try these tips

This post describes easy ways to revive a failed Time Machine backup. Users are encouraged to try Mac cloning to preserve their Mac data against loss.

Apple’s Time Machine feature is quite a handy utility for automatically backing up all Mac data. All you have to do is simply schedule how frequently you wish to back up, what destination you wish to back up to, and what data you want to back up, and the TM will handle the rest.

However, at times, the utility fails to create backups. This could be due to several reasons and if you get stuck due to any such errors, there are quite a few things you can do.

First things first – Identifying The Issue!

Before we delve into the solutions, let us first understand how we can identify Mac backup failure:

  • If the backup fails, the TM sends error messages in the form of notifications. However if you missed such notifications by chance, go to Time Machine Preferences. The red colored word Failed displayed against the label “Latest Backup” will indicate that the backup terminated unsuccessfully. 
  • If you use rotating backup disks, a red colored information icon against your TM disk will indicate a warning.
  • If you’re backing up for the first time, the TM can take several hours to ‘prepare’ for the backup. However, if it is stuck at ‘preparing’ even after running it overnight, there may be issues.
  • If the backup process starts transferring data to the target disk but gets stuck mid-way, then something is not working right.

If you observe any of the above indicators, immediately take the following steps - 

What you should check if the TM fails?

  • Ensure your backup drive (external hard drive, Time Capsule, macOS server on your network, etc.) is properly connected to your Mac 
  • Check if the drive appears in the Disk Utility
  • Check if the backup drive is compatible with the TM and your Mac
  • Check if all your Mac software is up-to-date
  • If you use AirPort Extreme Base Station, ensure its firmware is up-to-date
  • Check if your network connection is working
  • Make sure your backup drive is working
  • Ensure the backup drive has enough space to store a new backup
  • Ensure the backup drive is formatted like a Mac startup disk (Mac OS Extended (Journaled) with a GUID partition table)

If you’ve ruled out all of the above possibilities and the TM backup still refuses to complete, read on to learn the possible fixes.

How to fix a failing Mac backup

  1. Follow the below mentioned steps to get TM backup running again:
  2. Stop the TM if it is still in a “hung” state. For this, go to the Time Machine control panel and slide the On-Off button to ‘Off.’ This may take a couple of seconds to stop but it will do so eventually. Then restart your Mac and try again.
  3. If stopping TM doesn’t work, try to turn off the Mac using the power button. Ideally it may not be required, however, if the TM keeps running, it won’t let your Mac shut down properly anyway. Then boot your machine.
  4. From Finder, locate your backup disk and look for a file that has the word ‘sparsebundle’ in its name. Double-click this file to initiate a volume check. Once the check finishes, it will mount the disk image and a folder of your Mac’s backup will appear. 
  5. This folder will generally have a lot of dated folders indicating the different backups that were already stored on the disk. Additionally, there would be a file ending with the extension ‘.inProgress.’ This is the file that the TM creates internally while backing up your data.
  6. Delete the ‘.inProgress’ file. 
  7. Reboot again and turn the TM back on from the Control Panel. Wait for the ‘preparing’ stage and once that is done, hopefully, it should work.

Note: If while trying to delete the ‘.inProgress’ file, you encounter an error pop-up saying that you don’t have the appropriate permissions, then select the file in Finder and then press Command + i. Thereafter, click the padlock in the lower right corner and check “Ignore permissions on this volume.”

Wrapping it up

While the above mentioned steps are sure shot solutions, however, if they don’t, then you could try out other quick fixes like finding out which file is creating a problem for the backup (type cat /var/log/system.log in Terminal) and exclude that file from the backup.

You can also go to TM preferences > select Change Disk > reselect the backup drive or erase the backup drive and start over. You may also clone the Mac hard drive to preserve all your existing data using a utility like Stellar Drive Clone.

In fact, cloning your Mac hard drive is a good step since one of the reasons behind failing of a TM backup could be bad sectors on your backup drive. Therefore, creating a clone of the drive will ensure you have an entire copy of the data on the drive before you erase or reformat it.

Author: Vishal Chaudhary, Stellar Information Technology





I had the same problem and error. Tried re-formating the backup drive. Tried re-wiring it. Tried cleaning up seldom-used documents from disc. Noting helped. Eventually I used the following command in Terminal to view the activity log on my mac filtering only messages that have to do with Time Machine: log stream --style syslog --predicate 'senderImagePath contains[cd] "TimeMachine"' --info It took some time but I have been able to trace through the log messages one folder that was causing the backup to fail. I have removed the folder and the next backup completed just fine.

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