How to Setup Time Machine with a Networked Drive (Mac OS X)

Backing up my computer is something I’ve mostly lazy to do pretty much my whole life, with the exception of things like movies and music. This has mostly been due to the fact that I never really found any software that made it really easy to schedule and perform the backups without any user intervention and would also do it when it’s convenient for me. At work we use Acronis to back up the server and Cobian Backup for my computer, both which are very simple to set up and maintain and are quite user friendly. But they also provide things like network backup which is fantastic for an office situation.

I’m a Mac user at home and until Leopard where Apple introduced Time Machine, I never really bothered to look for any backup software because unless Apple has developed the software, a lot of open source software for Mac can have interfaces that are rough around the edges and can be quite buggy. Time Machine on the other hand has a great UI and backs up all your data in a way that is far easier to recover lost data and even presents it to you in a way that you can browse a single folder all the way back just as you would navigate through Finder. It wasn’t until this past weekend however that I decided to actually utilize this feature of Mac.

It had been my understanding that you could use virtually any hard drive you want to backup so long as it was HSF+J formatted.

However there are a few problems with this that I think a lot of users will experience and that is that most people want to backup onto a drive that they can actually utilize with other computers. Such as a networked drive on a NAS, a server or a Windows partition/networked computer that has a lot of free space.

Recently I bought a Netgear WNDR3400v2, which btw is a great router for a great price (dual band 5GHz and 2.4GHz), which supports a NAS as any USB drive that you plug into it. I didn’t want to have to plug in an external drive every time I wanted to backup my computer, especially since Time Machine does it hourly. So I thought it’d be great to utilize the NAS as a backup drive and as a quick swap between computers. But I ran into some problems and here are some helpful steps I’ve taken from a couple of sources that helped me out quite a lot.

  1. To use a network drive as a backup, it first has to be mounted to your computer. To do this, Open Finder, under SHARED select the network drive you want to back up to and connect to it. It will ask for credentials so put them in as you have set it, likely you can just click on guest.
  2. Next you’ll have to open Terminal, you can do a spotlight search and it will be the first one.
    1. In Terminal type: defaults write TMShowUnsupportedNetworkVolumes 1and press enter.If you go to Time Machine now, you’ll notice that the drive you want to use is displayed. Don’t try and set it up yet because you’ll run into an error.
  3. For the next step, you’ll need a bit of information. The name of your computer as it is shared on the network and the Mac Address of your ethernet. To get this information you do this:
    1. For your computer’s name go to System Preferences and under Sharing, copy your computers name without the .local. I suggest you paste this into a text document so you don’t have to type it out.
    2. To get the Mac Address of your ethernet type this in Terminal: ifconfig en0 | grep ether. Where ever you’ve copied your computer’s name to, add an _ and place the Mac Address at the end of it without the :. For Example, mine is Ryan-Boudreaus-Macbook-Pro_00254b1d5556.
  4. Next we have to create a sparsebundle. This allows Time Machine to utilize the hard drive as a “Time Capsule”. Sparsebundles are essentially just disk images where data can be moved in and out and allows for backups to be used more efficiently. To do this, there are two ways, the way I found easiest and least time consuming was to use a Terminal command. It can also be done through disk utility and just change the file extension, but Terminal is much quicker.In Terminal type: hdiutil create -size 100g -fs HFS+J -volname "Time Machine" NAME_XXXXXXXXXXXX.sparsebundleGive it a few seconds.To break that down for you: -size 100g is the size of the sparsebundle that you want to create in GB. I was using a 250GB so I typed -size 240g (just to be safe). However much space you want to allow for the backup is what you type there.

    The next important part is NAME_XXXXXXXXXXX. Remember I told you to leave your computer name and mac address some where to copy & paste? This is why. You’ll have to type it a couple more times too. For example, mine was Ryan-Boudreaus-Macbook-Pro_00254b1d5556.sparsebundle .

  5. This next step can be done in two ways that are equally quick. I recommend sticking with Terminal but I’ll say both ways.
    1. The first, locate the sparsebundle and drag and drop it to your network drive. Then Time Machine is almost ready to use.If you’re on Snow Leopard, you’re done. Just delete the sparsebundle from your hard drive, Terminal command will be step 6.
    2. Terminal method: Type: rsync -aE Name_XXXXXXXXXXXX.sparsebundle /Volumes/DRIVE/Where Name_XXXXXXXXXXXX is the same as before, and DRIVE is the name of network drive it is that you’re using.Give it a few seconds.
  6. All that’s left for Snow Leopard users is this command here: rm -rf NAME_XXXXXXXXXXXX.sparsebundle
  7. For Lion however, we have one more step. Download this script and run it in Terminal. To do that, navigate your way to where ever it’s saved and type ./ It’s a shell script written by msft.guy that is a work around allowing non-timecapsule drives to be used for Time Machine. It requires sudo so you’ll have to type in your password.

And that’s all. Here are links to the various guides I referenced:

NeoZenCortexis, 2

– Ryan


Author: Ryan

Ryan is a Quality Assurance Engineer II at BBM and graduated from Ryerson in 2012 with a degree in Computer Science. Ryan is a huge fan of video games, comic books, and rock music. Any opinions expressed are explicitly Ryan’s and do not reflect the opinions of his current, former or future employers in any way. You can follow him on Twitter: @ryan_boudreau

5 thoughts on “How to Setup Time Machine with a Networked Drive (Mac OS X)”

  1. Hello, trying to set this up so I can back up my mac with the same router and a 1TB external HD. Question is this: I am following the terminal commands, but the sparsebundle being created has a space of only 476.3 MB, when I requested using terminal commands to have the sparsebundle have a capacity of 4.5 gigabytes. Does my available hard-disk (on my mac) have to do with the limitation of the sparsebundle? Seeing as how I’ll be dragging and dropping the sparsebundle into the external HD via the network share drive.  Thank you for your time!

  2. Hi Thomas,

    The sparse bundle you create is limited by the amount of available space on the disk you are creating it on. When creating the sparse bundle you could try navigating to the network drive through terminal before creating the sparse bundle and that may allow you to create the sparse bundle directly on the drive.

    I’d try this out for you but I’m several thousand kilometers away from my network.

    Best of luck!


  3. Directions worked, I’m currently backing up my MBPro on my network hard drive. If I want to back up another MBPro with this menthod, do I need to create a separate sparsebundle for each computer?

  4. I followed these instructions, the drive is visible in time machine, but after it attempts to log in it comes up with “Operation could not be completed. (OSStatus error -6602.)”

    Any ideas?

  5. Hi David,

    It seems like 6602 is a common error that happens with even Apple’s Time Capsule. As you mentioned it seems to have something to do with logging into the network drive. The drive needs to be mounted with the same user account it was setup with I believe.

    Assuming you’re using a similar setup to what I did, otherwise you probably wouldn’t be here, I found this forum post that may be able to help with your issue.

    I recently updated my computer to mountain lion and seem to have lost connectivity to the time machine I set up so I’ll be re-running these steps myself sometime and they’ll probably need a bit of updating.

    Thanks for reading and for the comment!

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