Replaced MacMini HD and now Time Machine does not recognizes old backups

Discussion in 'Mac mini' started by sql-lover, Sep 12, 2013.

  1. sql-lover macrumors newbie

    Sep 12, 2013

    New to the Mac forums but being using Macs for more than a year.

    I recently replaced/upgraded my MacMini's HD due hardware failure. It was still working but about to die. So I had the chance of cloning the HD before replacing.

    I put a 1GB hybrid HD. But Time Machine immediately triggered a FULL backup instead of a Differential, as it usual does, and filled my external USB backup drive.

    How can I force or make Time Machine to continue running DIFF instead? I guess that Time Machine detected it as a new HD and that's the reason why it insists in a FULL.

    Any help is highly appreciated.
  2. Fishrrman macrumors G5


    Feb 20, 2009
    In the future, abandon Time Machine and adapt CarbonCopyCloner.

    Do so, and you will never be bothered with problems like this again!
  3. sql-lover thread starter macrumors newbie

    Sep 12, 2013
    Hmm ,

    What about the present and a way to solve the problem now?

    By the way, I used CCC for the HD migration. But my question is about how to avoid a new FULL and continue using DIFF. I'm sure is related to the HD GUID or some form of file ID on those backup files.
  4. Brian33 macrumors 6502a

    Apr 30, 2008
    USA (Virginia)
    Hi --

    I'm not sure, but I don't think there's any (practical) way to stop TM from doing a full backup when the source drive is changed. TM knows it's a different drive. It uses something called UUIDs to tell drives (volumes?) apart, but I don't know how it gets these UUIDs. Perhaps it is possible to spoof them or fake them, but I really doubt that's advisable.

    Seems like the best option is to erase your backup disk and let TM start over. Of course, once the initial backup is done TM will go back to doing "incremental" backups of just the files that have changed.

    The only downside is that you'll lose your backup history, so you won't be able to retrieve old versions of files or files that are no longer on your main hard drive. But TM backups are not intended to be archives; you hopefully aren't using TM to keep copies of files you really want to keep but aren't on your source drive...
  5. sql-lover thread starter macrumors newbie

    Sep 12, 2013
    I think I found a way (via UNIX or command prompt) to fix it, but I am not at home, I will try to check later.

    It looks like the UUID is embedded somehow and I need to reset it, so it can use the one from the new HD. That way, TM won't believe I have no FULL backups and it will continue re-using my previous backups.

    I honestly do not want to loss backups of over a year, and I am kind of surprised that Time Machine has this flaw. It looks there is a command on 1.7 that fixes the issue, but I'm on 1.6 (if I recall well) so I can't run that command.
  6. Brian33 macrumors 6502a

    Apr 30, 2008
    USA (Virginia)
  7. Ledgem macrumors 65816


    Jan 18, 2008
    Hawaii, USA
    Just to clarify, the issue is that your main system drive was failing, you cloned it to a new drive, and then Time Machine started an entirely new backup series. Is that right?

    The only way that I know of to have Time Machine continue from where it left off is to use the Migration Assistant. As of OS X 10.7.2 you can boot into recovery mode from a Time Machine volume (a volume created with OS X 10.7.2 or later). Whether you boot from Time Machine itself or from the built-in recover partition, you should be able to restore from a Time Machine backup onto a new (blank) hard drive. If you do this then the computer will behave as if nothing was ever changed. In my experience, Time Machine picks up from where it left off. I don't know if there are any other variables involved, though.

    If you're changing computer types (Macbook Pro to a Macbook, for example) then Time Machine will not allow you to restore. Instead, you will need to install the operating system and then use Migration Assistant to pull the data from Time Machine. I've done this once before but I can't remember how Time Machine responded.
  8. sql-lover, Sep 14, 2013
    Last edited: Sep 14, 2013

    sql-lover thread starter macrumors newbie

    Sep 12, 2013

    This is what I did

    Partitioned new HD but renamed it (I think this is the root cause)
    Cloned broken drive with CCC
    Swapped drives
    Started OSX

    The new HD is a clone , so it should not be a problem unless UUID it's embedded.

    But in Apple forums someone pointed me to renaming current hostname to what it was before. Now TM is showing Jan 2012 as oldest and Sept 9 2013 as latest which makes me believe its fixed now. However, current backup is around 200 GB so it seems its running a FULL? Don't know why, unless it is the time for a fresh FULL.

    ** EDIT **

    The trick did not work :-(

    I entered into TM and while I can see the old backups , I can't select them or do anything with them. Clearly, they have not been identified as previous backups, hence the reason for Today's FULL.

    Ohh boy ... I'm about to give up ...

Share This Page