How to do time machine back up?

Discussion in 'macOS' started by Freida, Jan 28, 2014.

  1. Freida macrumors 65816

    Oct 22, 2010
    Hello guys,

    could you please help me out with this? I have a rMBP which I want to backup and I have a 2TB (and another 1TB) drive with already some backup from MP. When I got the rMBP I simply backed up my MP and then on rMBP I restored from that backup.
    I always have 2 back ups so when I tried to backup my rMBP with the 1TB drive I thought it would just add to the backup that is already there but instead the old backup of the MP got deleted and then I got fresh backup. It was ok as I still have the 2TB so I thought no big deal.
    Unfortunately now, the 1TB is in another location (another country) and I need to backup my rMBP with the 2TB drive without losing the original backup that is there from the MP. I'm afraid that it will again delete the existing backup. Is there a way to prevent it? Shall I just rename the backup folder or something? Or do I match the harddrives names so the backup is added rather than erase/replace?
    What is the correct way, please?
  2. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    You should get a prompt asking if you want to inherit an existing backup, or start a new one. But I have seen reports of people saying they never saw that prompt and the drive got wiped.

    Here is what I would do, just to be safe.

    Make sure TM is turned off, then attach your drive. Open Disk Util and look at how much space is currently being used on the drive by the backup. Let's just say it is 320GB for example.

    Now use Disk Util to shrink down that single partition to a little over 320... say make it 350GB. Just follow this guide to resize the partition. This will not erase your data.

    Now click the + at the bottom to add a second partition of whatever size you want. You can add one of 650GB (using my example) if you like to use up the rest of the drive. Just name it whatever you want as long as it is different than the first partition, then click apply.

    Now go back to TM click the select disk button then select your new partition, then turn on TM. This will ensure the new TM backup is o the second partition and your old backup is untouched on the first partition.
  3. Freida thread starter macrumors 65816

    Oct 22, 2010
    Alright, thank you. That sounds like a great solution.


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