My situation is the following. I have an external HD (320 GB) and where I've set-up Time Machine backups since about 2 month now. I really love it except for the reason that my external HD is not network-capable. So for doing backups I have to manually attach the ext-HD (via USB) to my MacBook.

So today the idea came to my mind to make these Time Machine backups over the network. Basically I have an "old" Win notebook which I use somehow as a server for some stuff. It is more or less always connected to the network, so I could attach the external HD to that notebook and share it on the internal network. This post describes an approach that enables Time Machine backups for SMB shares.

Now before switching I first wanted to ask for some experiences among you. Did someone already try this out? Does it work well or is it not advisable and I should simply continue with my manual-usb-plugging backups?


I now tried to configure my Time Machine for the backup to the network share. I created the sparse bundle as suggested with the following command:

hdiutil create -library SPUD -megabytes 198000 -fs HFS+J -type SPARSEBUNDLE -volname "Juri's MacBook Pro_0025004696d8.sparsebundle" "Juri's MacBook Pro_0025004696d8.sparsebundle"

The "0025004696d8" is the mac address of my wireless device on my mac. So I copied the sparsebundle to the network drive. The I've chosen the mounted network drive on time machine and started the backup. For a while it displayed "making backup disk available" and then the error message "The backup disk image '/Volumes/timemachine-1/Juri's MacBook Pro.sparsebundle' could not be created (error 45)".

It seems as if time machine tries to create a new sparsebundle rather than using the one I copied there...Could someone please help me?


Sorry, now it works. The hostname has to match perfectly, otherwise it won't work. This link helped me a lot (for future reference).

  • As for the MAC Address: as far as I know, it should be the address of the first network card (like as listed as en0 in the output of ifconfig). On many Macs, that's the built-in ethernet card, not the built-in AirPort card. – Arjan Jan 13 '10 at 21:26

I do Time Machine backups for two MacBook's across the network using SMB and Windows Home Server and have had no problems. It is tricky to configure however once running it really works well. I have had no major issues except forgetting to set my exclusion list correctly, and Time Machine runs happily over wireless and wired LAN.

After the initial configuration it has really been set and forget. There is a ServerFault question here with links and details on how to set it up. It mentions WHS specifically but will work for any Windows Server Setup or even Windows XP/Vista/7 client machines using SMB shares. Just remember to enable the guest account for sharing.

  • Thx for your answer. Do you have any knowledge about the issue Bentem rose in his post? I never had to do a full system restore, but will it work wth bkups on a network share?? – Juri Jan 12 '10 at 20:28
  • As far as I know a full system restore using the image discs is not possible, however you can re-install the OS and once done restore the Time Machine backup. – BinaryMisfit Jan 12 '10 at 22:01
  • I see. Well, I guess I'll give it a try. In the worst case I have to reformat the disk and roll back to manual backup by plugging it via USB – Juri Jan 12 '10 at 22:39

Just a thought:

I did not read the linked article, but: enabling backups is one thing, while restoring might need some more tweaks? I kind of doubt the installation disc will offer you to restore a full system when it's on an SMB share.

  • good point...I didn't thought of restoring a full system. Single files/directories should be possible, but recovering a full system from a net-drive will be difficult...you're right. But how does it work with net-shared TimeCapsule? The only thing is that my HD will be formatted as FAT32 for being able to expose it as a share through a Win server.. – Juri Jan 12 '10 at 20:08
  • I don't know. But FAT32 will give you problems if you have files larger than 4GB though. Also, if the articles you found do not explicitly say that FAT32 is supported: see "Time Machine stops backing up to external disk" at support.apple.com/kb/TS1550 – Arjan Jan 12 '10 at 20:32
  • Well, thinking of it I may also use NTFS format since I don't necessarily have to mount the drive on the Mac directly but just over the network. Thx for the link, I'll verify it. – Juri Jan 12 '10 at 20:40

Once upon a time I had a setup that was tweaked to allow a Mac to do Time Machine backups to a file hosted on an SMB share. (Time machine sets up a sparsebundle disk image file that appears to your Mac as a standard HFS volume.)

I found that this setup was very fragile; I abandoned it when I experienced corruption of the sparsebundle which caused the backup to go poof. Also it was incredibly slow. It took more than a day to do the initial backup of <20gb of data.

I've since retooled to mounting the share over AFP and have found that to be much more resilient to network and backup interruptions. I'm backing up to a FreeBSD server though, so I can't advise you on how to do that with Windows.

  • The workaround for this is to create the SPARSE bundle manually and copy it to the server. A 60GB time machine backup of my system took just under 30 minutes on a Gigabit network. – BinaryMisfit Jan 12 '10 at 22:03
  • I misspoke - the sparsebundle was created manually. In multiple attempts, I never had a backup go as quickly as you described. – herrtodd Jan 15 '10 at 19:48

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