Time Machine Help

Discussion in 'Mac Basics and Help' started by Paul.Alx, Jul 27, 2014.

  1. Paul.Alx macrumors newbie

    Jul 27, 2014

    If I use a 1tb external HD that already has 400gb of seperate data on it, and then use it as my backup for Time Machine, will it overwrite the current data?

  2. AxoNeuron macrumors 65816


    Apr 22, 2012
    The Left Coast
    What I do is create a separate partition for time machine. First, back up the drive. Then, go in to Disk Utility and shrink the current partition. Finally, add in a new partition and use that for time machine. You can google it for a more detailed how-to but again I cannot stress how important it is to back up the drive first before you even open disk utility.
  3. Paul.Alx thread starter macrumors newbie

    Jul 27, 2014
    Thanks Axo, I'll probably just buy a new hard drive instead to save the trouble. If I back up my whole MacHD onto an external HD and then delete content off my MacHD, when Time Machine next backs up my external HD will it erase the content I erased and copy my current MacHD?
  4. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    Time Machine will always update the backup drive to the current version of what you have, but no it will not remove old deleted files from the backup disk right away. TM is designed to keep "versions" of your system so if you decide you need to go back and retrieve something you deleted say a week ago you could.

    Eventually as the backup disk gets full TM will purge off that old data, but it will not do it right away.
  5. Alrescha macrumors 68020

    Jan 1, 2008
    The answer to your question is "no", Time Machine will not touch your data. You can share a disk with Time Machine without worry, although Time Machine tends to keep the disk mostly full - this could interfere with your workflow if you tend to copy large files to that disk.

  6. gnasher729 macrumors P6


    Nov 25, 2005

    Step 1: Buy the biggest external hard drive that is sensibly priced. For example, right now I can get 2TB for £60, 3TB for £75, so I would buy 3TB. Make sure that hard drive has no fancy features. If it says "Mac compatible" you just pay extra (all hard drives are Mac compatible). If it says "Backup" in the hard drive name, you just pay extra for backup software that is going to interfere with Time Machine. Yes, if you want a hard drive to backup your Mac, avoid one that says "Mac" or "Backup" in its name.

    Step 2. Backup your Mac to the Time Machine drive. So now you have all the files twice, in case of some disaster, and everything is safe.

    Step 3: Move whatever files you want to move to your old external drive, and back it up as well. Only then delete the old files on your Mac.

    Initial Time Machine backups take ages. Don't worry about that. You can use your Mac while the Time Machine backup is running.

    If you are worried that thieves could steal your backup drive and get all your data, Time Machine lets you encrypt the backup drive. It makes no difference to the operation except that you have to enter the password for the backup drive sometimes.

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