Use time machine to backup external hard drive (not main one)

Discussion in 'Mac Apps and Mac App Store' started by desmond, Jun 2, 2008.

  1. desmond macrumors newbie

    Apr 11, 2007
    Hi all,

    I've searched for information on this and getting nowhere. Not sure if it's possible, but I have two hard drives now as I've run out of space on my laptop. So therefore I really use one of the hard drives for my main storage and drag files across to the other one to back that up.

    It would be easier if I could just use time machine to back up the one hard drive to the other. I don't want to just replicate what's on my hard drive.

    Does anyone know if this is possible? Would appreciate any help.

  2. georgeoommen macrumors regular

    Apr 12, 2007
    if its attached via USB or firewire, then yes its possible.. just go into time machine preferences and make sure its not in the Exclude list (Click the options button). you're good to go..
  3. desmond thread starter macrumors newbie

    Apr 11, 2007
    Thanks for your reply, both external hard drives are USB. I've set it up so the second external Hard Drive is the one I'm backing up to, but I can't choose from the list that I only want to backup the first external Hard Drive and not my laptop hard drive.

    In the options it gives a list of what to exclude from the backup. I would like to exclude my laptop hard drive and just have the first external hard drive as the one to be backed up.

    Is this possible?
  4. desmond thread starter macrumors newbie

    Apr 11, 2007
    Sorry, I've been a bit daft here. You can actually just add your Macintosh HD to the list of "what not to backup". However, for some reason I can't exclude any of my external drives from the list, they appear automatically and the minus button becomes disabled when I have them selected.

    So, I can only really choose whether I want to include or exclude my Macintosh HD from that list, does that sound right? Was hoping I could use time machine to back up 2 external hard drives.
  5. badger128 macrumors newbie

    Feb 24, 2011
    i seem to be having the same original problem. i have an IMAC with 2 external hardrives connect via ethernet (router). one of them is set up for time machine and works great in backing up my internal IMAC hardrive, however no matter what i do i can not get time machine to back up my second external hardrive, which is annoying as i store all of my media files on this second drive!

    is it a case of having to plug it in via firewire/usb?? this isnt really a good answer as file transfer would be too slow!

    any help would be much appreciated

  6. pengkeu macrumors newbie

    Aug 2, 2011
    Back Up Sources Must be Mac Formatted

    Hi there,

    I want to do the exact same thing (back up both my internal HDD and a portable HDD to my external HDD), so the previous information was very helpful. To repeat, here is the process: Go to System Preferences --> Time Machine --> Options... and select the drive(s) you want to back up. Then click the - button at the bottom of the window so those drives will be removed from the list of excluded locations (i.e. backed up).

    The key to remember, though, is that the drives you want to back up MUST be formatted for the Mac. That means FAT-formatted drives usable with Windows cannot be backed up. Your choice is to either reformat your FAT drives as HFS+ (using Disk Utility) or simply use another back up utility. You should also be able to partition your external drive as HFS+ and FAT, and back up the HFS+ partition. Again, keep in mind that your Windows-compatible partition cannot be backed up using Time Machine. All the more reason to keep your files on HFS+ drives and resort to the mediocre FAT format only as necessary.

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