Can't Access Time Machine backups after clean OS X install

Discussion in 'macOS' started by Brian33, May 16, 2016.

  1. Brian33, May 16, 2016
    Last edited: May 16, 2016

    Brian33 macrumors 6502a

    Apr 30, 2008
    USA (Virginia)
    [Couldn't find more appropriate forum]

    My MBP was running 10.8.5 (Mountain Lion) and had Time Machine backups going back to September last year. I re-formatted the drive and did a clean install of 10.11.3 (El Capitan) in April. I gave it the same machine name as it had before (simply "macbook").

    I expected that even though I had used the same machine name, there would be a new unique identifier of some sort associated with it, and that OS X and Time Machine would behave as if this was a new (never before seen) machine.

    I was surprised when I turned on Time Machine to use my Time Capsule, it started backup up to the existing "sparsebundle" file (i.e., "macbook.sparsebundle") which had been created while running Mountain Lion. I believe it did a full backup, as one would expect, but it seemed to be preserving the old backup history. I thought, "pretty neat!"

    However, when I recently tried to restore a file from before my El Capitan install, the Time Machine interface shows the backup dates all the way back to September, but anything prior to April is "greyed out" and inaccessible. The interface won't "zoom back" to those dates, even to list the files.

    Are these old backups accessible in some way?

    If so, I might keep them, although I don't really feel a need to.

    If not, I wonder why Time Machine didn't either delete them or start a fresh sparsebundle file. That's what I expected to happen. To me this seems like a (minor) bug in Time Machine -- that it added on to the old backups yet doesn't allow access to them. I wonder if it can even delete these old backups when it comes time to thin them out.
  2. Bruno09, May 17, 2016
    Last edited: May 17, 2016

    Bruno09 macrumors 68020

    Aug 24, 2013
    Far from here

    Once in Time Machine interface, hit : Cmd + Shift + c (= go to the computer)
  3. Brian33 thread starter macrumors 6502a

    Apr 30, 2008
    USA (Virginia)
    You Sir, or Ma'am, are correct -- Thanks! I never would have thought of that. After doing Cmd+Shift+c then I noticed two items under the "Devices" entry in my Finder sidebar, one with the current internal drive name, and one "macbook", which I think was the drive name it had before I reformatted it. It's not obvious which backup dates are valid for which device, but it works.

    I really like and have had good luck with Time Machine, but it would be nice if Apple would spend a little effort improving the user interface.

    By the way, do you know how to restore files that belong to another user? I'm admin and have password, of course, but I don't see any way to do that in the interface. Do I have to "ignore ownership" on the backup disk image somehow?

    [I (purposely) changed the UIDs of all the accounts when I did the fresh OS X install, and now the on-disk owner UID number doesn't match with the new account UID number. (I.e., I used to be UID 504 but now I'm UID 502.)]

    Anyway, thanks for your help.
  4. Erdbeertorte, May 18, 2016
    Last edited: May 18, 2016

    Erdbeertorte Suspended

    May 20, 2015
    With the Root = Super User = System Administrator you should have access to all files in the Finder. You can activate it in System Preferences - Users & Groups - Login Options - Unlock with your Password - Network Account Server "Join..." - Open Directory Utility - Unlock with your Password - Edit in the Menu Bar - Enable Root User - Set a password for it.

    After that you can login with the name root and it's password.

    But be careful you can delete everything in that account. Don't use it as a regular account.

    Screen Shot 2016-05-18 at 17.26.55.png
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    Edit 1: added screenshots

    Edit 2: added missing second screenshot
  5. Brian33 thread starter macrumors 6502a

    Apr 30, 2008
    USA (Virginia)
    Ah, that sounds familiar -- I'd forgotten about that, thanks. It seems like an awfully convoluted process for what I would think would be a fairly common need, though. I might just as well attach the backup disk image and use 'sudo' in Terminal to find and copy the files. I'd hate to try to talk my mother-in-law through either process over the telephone, though! Again, I wish Apple would improve the user interface to Time Machine.

    But, it is possible, and that's what counts the most. Your reply makes me wonder if enabling the root user is the only way to get access to all files in Finder? I can and do use Terminal, but sometimes I have wanted to be able to quickly move something directly into one of my kids' accounts directories with Finder...
  6. Erdbeertorte Suspended

    May 20, 2015
    You can see all hidden files with the following command in the Terminal:

    defaults write AppleShowAllFiles YES
    killall Finder
    The second one just restarts the Finder. Don't do it while copying/moving anything or things like that.

    With sudo you can also move every file I think if you are familiar with the commands. It's like you are root then. If you want to do it in the Finder there is no other way than logging in as root.

    Maybe disabling SIP (rootles) could work. I don't know. I have only my own account. But I have it always disabled and can access files in my old accounts from another Mac on external drives without a problem.

    You have to boot into the recovery partition by holding cmd+r and there just enter in the Terminal "csrutil disable".
  7. Makanan macrumors newbie

    Jul 26, 2018
    Thanks Bruno! It's a lifesaver!
    --- Post Merged, Jul 26, 2018 ---
    Hi Bruno, after the clean install, the Mac says the external USB drive that houses the Time Machine backup files is read only and will not allow me to make new TM backup. What to do?

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