Does Disk Utility's Repair Disk Permissions Do Anything?

Discussion in 'Apple' started by Matthew Lybanon, Oct 26, 2013.

  1. Mac OS X 10.8.5.

    After installing several system updates I ran Disk Utility's Repair Disk
    Permissions. Because "Show details" gave a fairly long list of
    (presumably) repairs, I ran it again, just to see what would happen. It
    found what I think is the same list of things to repair (I didn't check
    every one, but it was a similarly long list and several items were
    repeats of items in the first list), and again claimed to fix them.

    I know it looks like I've answered my own question, but I'd like to know
    what other people think.
     
    Matthew Lybanon, Oct 26, 2013
    #1
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  2. Matthew Lybanon

    Lewis Guest

    Don't do that.
    Yep, that's a good example of why not to do that.
     
    Lewis, Oct 26, 2013
    #2
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  3. Matthew Lybanon

    J Burns Guest

    Is it iTunes? I've read that the latest update confuses Disk Utility's
    Verify Permissions.
     
    J Burns, Oct 26, 2013
    #3
  4. Matthew Lybanon

    Alan Browne Guest

    I haven't "repaired" permissions in over 3 years. JR will chime in and
    say it's all but useless (for reasons I don't recall).

    In short: don't bother.
     
    Alan Browne, Oct 27, 2013
    #4
  5. Matthew Lybanon

    Your Name Guest

    Repair Permissions is uesful for what it is designed to do (which isn't
    much) ... BUT it is definitely not the "cure all" solution which many
    people tend to believe it is.

    Since it doesn't take a huge amount of time nor do anything
    troublesome, it is perhaps worth trying as a first option. It's a bit
    like the usual help desk recommendation of switching the computer or
    modem off and on again - it may work, but it's not likely to fix any
    real problems. :)
     
    Your Name, Oct 27, 2013
    #5
  6. First of all it only works for Apple installed software that keeps a
    receipt, secondly it's only going to reset permissions on that set of
    software to what the installer thought at the time of install they
    should be, and thirdly - and related to my second point - you may be
    creating additional problems by changing permissions that were altered
    in ways that OS X never recorded, but were valid, even necessary.

    I can really only think of one instance since I began using and
    supporting OS X, that this process had any value. While the chances are
    slim that you'll create additional issues, the chances are even slimmer
    you'll fix anything you think may be permission related with Apple
    software.

    So I'd avoid unnecessary 'repairing' of permissions. I'm not even sure
    why Apple keeps that around. It's created more problems and wasted more
    time than it ever did any good.
     
    Jamie Kahn Genet, Oct 27, 2013
    #6
  7. Matthew Lybanon

    Alan Browne Guest

    It never solved anything for me so wouldn't bother.

    OTOH, "Repair Disk" has worked on at least one issue I had - though I
    had to boot into safe mode (or somesuch) for it to function.
     
    Alan Browne, Oct 27, 2013
    #7
  8. As I said, I ran Repair Disk Permissions after System Update (one of the
    programs updated was Safari). Is that Apple installed software that
    keeps a receipt? I have no idea.

    The point is, Repair Disk Permissions SAID that it repaired a long list
    of permissions, but when I ran it again all the same permissions still
    needed to be repaired.

    secondly it's only going to reset permissions on that set of
     
    Matthew Lybanon, Oct 27, 2013
    #8
  9. Matthew Lybanon

    Jolly Roger Guest

    Disk Utility's Repair Permissions function isn't as magical a tool as a
    lot of people seem to assume. It's a very simple tool that is meant to
    reset the states of ownership and permissions of *specific sets of
    files*, and *only* those files listed in the receipts of specific
    software in the receipts folder. This receipts folder is located at
    /Library/Receipts in Mac OS X versions prior to 10.6, and was moved to
    /private/var/db/receipts starting with version 10.6.

    Repair Permissions reads the contents of each receipt in the receipts
    folder to find out which files and folders it should examine. Receipts
    are typically created by software installers that use the Mac OS X
    built-in /Applications/Utilities/Installer program to install a software
    package, though they may be placed into the receipts folder by other
    means as well. Receipts typically contain a "Bill of Materials" file
    that lists of each important file and folder in the installed software
    package, along with the expected ownership and permissions those files
    and folders, according to the install package.

    Repair Permissions examines only those files listed by these receipts.
    This means the files in your home folder and the files in the local
    domain (/Library for instance) are *not* examined.

    The Repair Permissions tool has a rather serious design flaw: it does
    not know how to resolve cases where multiple receipts list the same file
    or folder with differing ownership and permissions. This actually
    happens fairly frequently, particularly when more than one software
    package installs and uses a shared library or other system resource that
    happens to be used by another software package. If there are multiple
    receipts that list a given file or folder, and the expected ownership
    and permissions differ between those two receipts, Repair Permissions
    will encounter the first receipt, change the ownership and permissions
    to honor that receipt, then encounter the second receipt and change the
    ownership and permissions to honor the second receipt. This typically
    manifests itself in Disk Utility's Repair Permissions log as a
    file/folder that never seems to be actually repaired, flipping back and
    forth between two states.

    Once you understand how it works, you see Repair Permissions is not half
    as useful or magical as a lot of people seem to believe. I wish more
    people understood this - we probably wouldn't see so many Mac users
    running Repair Permissions at the drop of the hat or on a regular
    schedule as we see so often. ; )

    Bottom line: If you are not experiencing problems with a specific piece
    of software listed in the receipts folder, there's no reason to run
    Repair Permissions.
     
    Jolly Roger, Oct 27, 2013
    #9
  10. Matthew Lybanon

    J Burns Guest

    What apps does the list say these permissions are from?
     
    J Burns, Oct 27, 2013
    #10
  11. Matthew Lybanon

    Király Guest

    Right on cue! He had his very long canned response right at the ready.
     
    Király, Oct 27, 2013
    #11
  12. Matthew Lybanon

    Lewis Guest

     
    Lewis, Oct 27, 2013
    #12
  13. Matthew Lybanon

    Jolly Roger Guest

    Guilty. : )
     
    Jolly Roger, Oct 27, 2013
    #13
  14. Matthew Lybanon

    JF Mezei Guest

    There is no love lost betwen JR and me. But in this particular case,
    Jolly's response was constructive and informative on how the repaid
    permissions work and factual about the areas where there are problems.
     
    JF Mezei, Oct 27, 2013
    #14
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