I just got a new MacBook Pro since I was due for a new machine and needed Lion for the new Xcode. I also got an Apple TV with the idea of centralizing all the digital media in my house by hosting it on my old Snow-Leopard MacBook Pro using iTunes.

I set up the new machine using my USB drive's Time-Machine partition and fixed up a few odds and ends and am now happily using Lion there. But I want to use the USB drive on the old machine as a Time-Machine drive for both machines.

But the new Lion machine doesn't see the shared drive from the old machine and I don't want to swap the drive around, I just want it to work as a backup when I connect to my home network. I've spent the afternoon reading articles on how to do this for various flavors of OSX but none of them address my configuration and now I feel over-saturated with information.

So, my questions are: First, can I do this? Second, where can I find good documentation on setting this up? I'm fairly technical and am not afraid of getting deep into the details if it will give me a painless way to do backups and I've grown to like the simplicity of Time-Machine. (Plus I use VCS systems for all the critical files in my day to day work).


  • If I understand you correctly, you want to store Time Machine backups from your new MacBook on an external drive attached to another Mac via USB? AFAIK this isn't supported.
    – nohillside
    Commented Jan 1, 2012 at 9:45
  • I think you need to run OSX server on the machine with the Time Machine disk
    – mmmmmm
    Commented Jan 1, 2012 at 11:03
  • @patrix, yes, that's exactly it! Thanks for clarifying it.
    – Fran K.
    Commented Jan 1, 2012 at 17:34
  • @Mark, Really? That feels like overkill for just wanting to route backups to a USB drive. I'd thought that I'd keep the old laptop available as a spare, if I install OSX server will that still be possible?
    – Fran K.
    Commented Jan 1, 2012 at 17:36

2 Answers 2


No. Most technically minded people have stopped trying to hack together AFP as Apple have changed the code to tighten up and only show legitimate sources not connected as direct attach storage.

Apple provides two products that let Mac Clients see a hard drive as a Time Machine backup when they are not connected DAS but instead NAS (network attached storage) which facilitates the sharing of one drive with multiple macs simultaneously and without reconnecting cables:

  1. TimeCapsule - only the internal drive is supported for Time Machine.
  2. OS X Server - can mark any share point as being available for Time Machine use.

Yes, anything is possible in software given enough money, time or ingenuity, but for reasons I can only presume is enough smart people breaking TimeMachine and blaming Apple for lost data when using DIY Time Machine targets, this has been tightened up in Lion to preclude any easy solution that is documented at present on the internet from working.

  • Do you mean "No, it is not possible at all" or "No, not with Apple's blessing"? I can't believe I'm the only one who would want to do this and I've seen plenty of articles on the web with people using linux to set up an AFP share and I assumed something like this would be possible on an old laptop.
    – Fran K.
    Commented Jan 1, 2012 at 23:00
  • Obviously the latter. You can see thousands of posts where people hacked together an AFP and it worked or they had problems. It's more that you are not supported by the built in commands unless you go the two avenues above. Many third party software and hardware advertise and have been updated for Lion so their drives appear as legitimate (and supported by them) destinations for Time Machine.
    – bmike
    Commented Jan 1, 2012 at 23:06
  • I edited my answer to be a bit more technical. Feel free to edit it further if needed to suit your question if I'm not really hitting the nail on the head. It's clearly not the answer you might hope to get so I'll keep my eyes peeled for solutions to DIY a Lion compatible NAS solution.
    – bmike
    Commented Jan 1, 2012 at 23:14
  • Thanks for taking the time to elaborate. It now makes sense why there is no solution that fits. I suppose I'll have to price out the cost of a server install versus a couple of new USB drives.
    – Fran K.
    Commented Jan 2, 2012 at 5:41
  • Server runs quite well in virtualization so you could just pay for parallels/vmware and the server OS and script it to start up the VM at night if you were worried about RAM or IO contention with your primary workstation. I haven't tried squeezing a Lion server yet to see if it runs with less RAM than 2G, but file sharing performance is quite acceptable even on an old Core 2 Duo MacBook Pro with a 160 Gb internal HD and only 2G RAM. Even 5 macs hitting it for Time Machine is as speedy as our dedicated mac mini server for that one task.
    – bmike
    Commented Jan 2, 2012 at 15:48

you can do this. I'm guessing the problem is your USB drive still has your time machine backup on it? Erase your time machine backup drive. Then set it as a shared device in system preferences sharing on your old macbook. Mount the drive on your new machine and select it as a time machine backup. I am doing this with two lion machines and don't know if it works with snow leopard to lion. But you could install lion on your old machine if it doesn't work.

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