Time Machine: new backup after erasing the drive

Discussion in 'Mac Apps and Mac App Store' started by msvadi, Feb 10, 2017.

  1. msvadi macrumors regular

    Joined:
    Aug 12, 2010
    #1
    I'm troubleshooting my Mac and have to erase and re-install the OS to see if the problems persist. No data from the backup is going to be imported, and the computer is going to be setup as new. If I use Time Machine with the same external drive, will it start a completely new backup or will it modify the already existing backup (created before erasing the drive)? I would like to be able to restore from the old backup after troubleshooting is done.

    Thanks.
     
  2. Sciuriware macrumors regular

    Sciuriware

    Joined:
    Jan 4, 2014
    Location:
    Gelderland
    #2
    Hi, I did exactly that recently:
    Open Time Machine Preferences,
    disconnect the TC drive (and all others you might use),
    mount the TC from Finder,
    erase it from Disk Utility,
    dismount it any way.
    open Time Machine Preferences again,
    assign the TC as backup again.

    In my case I had a second drive connected via the TC;
    I had to take it off and erase it separately on the USB port.
    ;JOOP!
    --- Post Merged, Feb 10, 2017 ---
    P.S.: before you erase the TC, copy the old backup to another place or you will loose it.
    If you do not wish to make backups during your troubleshooting, stop the backups by
    stopping the TC (f.i. [ ] Back Up Automatically) and/or disconnect/de-assign the TC as backup.
    In that case do not erase the TC.
    ;JOOP!
     
  3. msvadi thread starter macrumors regular

    Joined:
    Aug 12, 2010
    #3
    Thanks, but I actually need to make backups during troubleshooting - the issues I'm experiencing might be related to Time Machine and external drives.

    Does the external drive have to be erased? What happens if I don't erase? Moving 1TB+ of old backups to another location might be problematic.
     
  4. Sciuriware macrumors regular

    Sciuriware

    Joined:
    Jan 4, 2014
    Location:
    Gelderland
    #4
    You might try to rename the old backup as well, but the first backup after that will cause
    a vast volume of backup transfers, so you might run out of space.
    A temporary solution is to set the Time Machine options so that much of your private
    files are excluded, speeding up backup too. That option can be reset afterwards.
    ;JOOP!
     

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