Mac Backups

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Intial Setup

  1. Open Disk Utility, in the menu bar, select Go > Utilities > Disk
  2. In the menu bar, select File > New Image > Blank Image…
  3. Name the disk image in the “Save As:” and “Name” fields, then change
    the Image Format to “sparse bundle disk image.” You can then set the
  4. Keeping the default Format and Partitions, click the “Save” button at
    the bottom right of the window.
    • Error at 9 with this default Format. Solved by creating a new Timemachine.sparsebundle with Format: MacOS journaled extended rather than APFS. Did not use encryption (aes 128 used in URL) From
  5. The new sparsebundle will automount. Unmount it.
  6. Connect to the network storage share, in the menu bar, select Go > Connect to Server. Enter in the Server Address path, and click the Connect button.
  7. Open a terminal window, and use the mv command to move the .sparsebundle file to the share.
  8. Double click on the sparse bundle in Finder to mount it on the computer in /Volumes/.
  9. Run the following command to set the sparse bundle as the Time Machine destination: sudo tmutil setdestination '/Volumes/Untitled'
  10. You can then turn Time Machine on in System Preferences and confirm that the location is set to the locally mounted sparse bundle.


  • APFS format volumes (default format in 4) must be local hard disks. Remote drives must be formated MacOS Journaled Extended instead. (for nfs, smbfs, fusefs). I don’t encrypt.
  • To rename a drive so it is not just /Volumes/Untitled
    • sudo hdisk listand get /dev/disk#s# for the tmutil-attached device (/Volumes/Untitled). Then sudo diskutil rename /dev/disk2s2 backup

Remove Current Time Machine Drive

Stop backup from timemachine utility/taskbar icon. Any active backup lost?. See Hung Backups below.

tmutil destinationinfo. # get long ID number
sudo tmutil removedestination 0F7B117E-F0C8-4871-AB79-05A10F0ADEE
df -h # Get Volume name.  probably "Untitled"
sudo diskutil unmount force /Volumes/Untitled/

Hung Backups

If you kill a backup process while it is running, it can leave an work directory that can cause persistant hangups when next backup will stick forever in “In Progress” or “Preparing Backup”. You must remove the work directory before you run the backup again. Note that it may take a long time to “Prepare Backup” if it has been a while since the last good backup.

  1. Backup must be stopped. Turn off/Skip in TimeMachine icon/console.
  2. In Finder go to /Volumes/(backupdir)/Backups.backupdb/(HostName).
  3. Drag YYYY-MM-DD-TTTTTT.inProgress folder to Trash
  4. Start backups again.

BootTime Setup. (untested)

#! /bin/bash

test -d /Volumes/timemachine/mojave.sparsebundle && exit # already mounted.
sudo mkdir /Volumes/timemachine
sudo mount -t nfs -o rw,async,noatime,resvport /Volumes/timemachine
test -d /Volumes/backup && exit # already set.
sudo hdiutil attach -mountpoint /Volumes/backup /Volumes/timemachine/mojave.sparsebundle
sudo tmutil setdestination /Volumes/backup

Put this in a script, e.g. ~/bin/TimeMachineBoot.bash, make it executable, and run the script from

SystemPreferences > Users&Groups > YOUR.USER > [Startup] > [+] > ~/bin/TimeMachineBoot.bash`