I have a disk drive connected to my router that I'm using for TM backups. What I did is I created a .sparsebundle image using Disk Utility and then copied that image to my disk drive. Then, in Terminal I typed the following:

sudo tmutil setdestination /Volumes/MYCIFSvolume

All works OK, but I have to manually mount the .sparsebundle by double clicking it and then Time Machine recognizes the drive and make backups to it.

Is there any way TM automounts this .sparsebundle when a backup is scheduled?

I'm using OS X 10.9

Many thanks,

3 Answers 3


These instructions assume you're using a sparsebundle file in 10.9 because you use an encrypted drive. If not, modify accordingly.

First, follow the instructions in the link below to figure out how to use security find-generic-password to grab the password to your encrypted drive out of your Keychain programmatically.


Then create a file called mounter in your local bin directory ~/bin that contains the following code (replace all paths with your paths, and in the security find-generic-password, use the name of the key in Keychain):

#!/usr/bin/env bash -e

SPARSEBUNDLE_MOUNT_PATH="/Volumes/Time Machine/"

# Check existing states
if [ -e "$SPARSEBUNDLE_MOUNT_PATH" ]; then
    echo "Already mounted."
    exit 0    

if [ ! -e "$PHYSICAL_DRIVE_PATH" ]; then
    echo "Physical drive not attached"
    exit 0

if [ ! -e "$SPARSEBUNDLE_PATH" ]; then
    echo "Virtual drive not found on physical drive"
    exit 1

# The mount command uses security find-generic-password
# to get the password from the keychain store
MOUNT_PASSWORD=$(security find-generic-password -w -D "disk image password" -l TimeMachine.sparsebundle)
printf $MOUNT_PASSWORD | hdiutil attach -stdinpass -mountpoint "$SPARSEBUNDLE_MOUNT_PATH" "$SPARSEBUNDLE_PATH"

This is a bit verbose, but means no storing passwords anywhere but keychain. In any case, now we have to get it to run. Create a file in ~/Library/LaunchAgents/ like ~/Library/LaunchAgents/com.martorana.dave.mounter.plist and put the following code in it, replacing, of course, the paths with your own paths:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">

We're using launchd instead of cron for a host of reasons, the most important being access to your keychain.

Now load your launch daemon:

launchctl load -w ~/Library/LaunchAgents/com.martoranas.dave.mounter.plist

And that should do it. Now launchd will run your shell script every 60 seconds, and if not mounted and available, will mount your sparsebundle disk image.




Just one quick thing to try.

Is the image named machinename.tmp.sparsebundle? (where 'machinename' is the name of your machine not the text)

If not then try naming it like that and see what happens. That's the naming system that Time Machine uses for it's images.

  • Are you sure it's not just machinename.sparsebundle?
    – chmac
    Mar 5, 2019 at 19:56

I have a similar setup, but I indicated the backup disk in the Time Machine GUI. Time Machine then created the sparsebundle on its own.
In my case, Time Machine automatically mounts the sparsebundle if the backup disk is available.
I don't know how to get from your current situation to mine though.

  • How did you make time machine create a sparse bundle disk image? I've never heard of an like that, and I don't see it in 10.8.5?
    – Samuel
    Feb 22, 2015 at 4:18
  • My backup disk is connected to another Mac on my network. I've set this up a couple of years ago so I don't remember exactly, but I don't think I had to do anything special. Just indicate the backup disk.
    – Hobbes
    Feb 23, 2015 at 10:37

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