Fix Time Machine Backup failure in macOS

fix Time Machine Backup failure in macOS

Time Machine Backup failure in macOS High Sierra is very common and the fix for it varies from error to error. If you haven’t backed up your Mac for a long time, it is normal for Time Machine to take some extra time in comparing current files and folders to the last backup. The time for Time Machine to prepare backup may vary from a few minutes to a few hours. In case it gets stuck on preparing backup status for more than one day, then there is an issue. In this post, we are sharing tips to Fix Time Machine Backup failure in macOS.

fix Time Machine Backup failure in macOS

How to fix Time Machine Backup failure in macOS

First-time backup Error (-50): 

One common first backup error on macOS High Sierra is ” [] Error: (-50) SrcErr:NO Copying /Volumes/”, so if you see this error it could mainly because of the connected external drive used for Time Machine Backup.

Fix: Either the external drive format is an issue or the drive itself. You could change the drive or format it right to fix the error.

‘Stack Overflow’ Error: 

If you moved from Sierra to High Sierra and presented with ‘stack overflow’ error in Time Machine backup then this could possibly fix it. Follow the steps, and target a new backup drive for this.

Go to System Preferences > Spotlight > Privacy and add your Macintosh HD (local disk) to the list of areas that Spotlight should be prevented from searching

  • Click the Apple icon at the top left corner of your screen and choose System Preference.
  • Next, click on the Spotlight and choose Privacy tab.
  • Then, add (+) button to browse to your Time Machine backup folder and add it to the list, and close System Preferences.

If this still doesn’t fix the error then:

  • Go back to System Preferences > Spotlight > Privacy, and remove your Macintosh HD (local disk).
  • Give some time to the “mds” processes to re-create the Spotlight index (can be seen in activity monitor)
  • Go to Time Machine and Options, and reduce the backup size by excluding Folders (e.g. “System”, “Library”, “Music” folders)

If the backup runs correctly after this then you have few more things to do. Remove the exceptions of those folders, and include them for next backup.

Time Machine backup interrupted error

In case of this Time Machine error message, you need to resume the backup manually if it doesn’t back up automatically. Usually, as soon as the error fixes, Time Machine resumes backup progress itself. The error could be a network problem or accidental disconnection of backup disk.

Fix: To start a backup at any time, click the Time Machine icon in the menu bar. Then choose Back Up Now.

If Time Machine doesn’t back up certain files

As per Apple for macOS Sierra, If Time Machine doesn’t back up certain files, you are required to make changes to the list of excluded items in Time Machine preferences.


  • Choose Apple menu > System Preferences, click Time Machine, then click Options.
  • If a file you want to back up is in the list of excluded items, select it, and remove it.

The list of Time Machine error could go on, and on. We will try keeping this list of Fix Time Machine Backup failure in macOS updated. Let us know in the comments.

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