Help with Permissions.

Discussion in 'iMac' started by mattimoo, Mar 5, 2013.

  1. mattimoo macrumors newbie

    Joined:
    Mar 5, 2013
    #1
    Hi Please help i change the permissions on my HD to no access and now i can’t even boot my mac up.
    I do have a backup on time machine but what is the best thing to do as i have all my family picture on there.

    I changed the setting as I was worried that everyone could see my mac didn’t think I would lock myself out.

    Any help would be great thanks

    I have an iMac.

    :-(
     
  2. justperry, Mar 5, 2013
    Last edited: Mar 5, 2013

    justperry macrumors 604

    justperry

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    #2
    You are not the first one to make this mistake, there is no easy fix and even when you can "fix" it you need to reinstall, reason is that all your files folders have the wrong permissions and for security in the future it is better to completely reinstall the OS.

    The "fix" is to Startup in Single User mode and entering commands, first you have to mount the disk and than you need to run a command which resets all permissions to read/write so that everybody has rights on all files.

    Now, I will try to find this, if I still have those commands on my Mac I will get back to you here.

    Edit: There are two other ways to accomplice this, one is, do you have a bootable backup?, if so say so and I will guide you further.
    The other one is by installing a new OS on another (HD-USB) disk, again I will help further if you give the information needed.

    Edit again: Look here, this might also help you:

    http://forums.macrumors.com/showthread.php?t=1321974
     
  3. mattimoo thread starter macrumors newbie

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    Mar 5, 2013
    #3
    HI JustPerry

    Firstly thanks so much for your reply,

    What do you mean by (Startup in Single User mode) i have used mac’s for many years but as you will know they just never need any work doing to them so I’m not that technical with them.

    I have time machine attached to it would it be a good idea to rest the imac to factory setting and reinstall from last back up. ?

    *will it let me reset to factor setting if i have locked the perditions.??

    thanks









     
  4. mattimoo thread starter macrumors newbie

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    Mar 5, 2013
    #4
    bootable backup do you mean the time machine ?

    Thanks


     
  5. justperry, Mar 5, 2013
    Last edited: Mar 5, 2013

    justperry macrumors 604

    justperry

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    #5
    If you have a TimeMachine and it's a recent backup then startup in recovery mode, hold Command-R at startup, you then can choose to install from backup/TimeMachine, this is the easiest way out, but you loose everything after the last backup.
    If that is a lot and there are files needed then you could startup in Single User Mode and recover/change the permissions from there.
    So, first question, do you have any files needed on the HD aafter the last backup, if not go ahead and use recovery, if not don't.

    Single User Mode is as it says, only one User can be active, when you hold Command-S you get into that mode, it is all text based, no UI.


    The commands to enter in single User Mode to set all permissions to RWX are:

    fsck -y
    (return)
    mount -uw /
    (return)
    sudo chmod u=rwx,g=rwx,o=rwx /
    (return)

    (Takes a while depending on number of folders/files)
    After this run disk permissions.

    You could also try to go into disk Utility in recovery and try repairing permissions first there
     
  6. mattimoo thread starter macrumors newbie

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    Mar 5, 2013
    #6
    By files do you mean things like JPGs etc or system files as i done a backup only a few days ago.

    when i do a Command-R at start up i was thinking it wouldn’t let me as i have no permission now.

    sorry for all the questions i am just a dead man if i loos all the family pictures :)


     
  7. justperry macrumors 604

    justperry

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    #7
    I updated my last post, especially the last BOLD sentence is important.

    So, do this first and nothing else yet.
    Startup in recovery, open Disk Utility there from the Menu Bar, then click on the HD and repair permissions on that disk, this might solve all your problems.
     
  8. mattimoo thread starter macrumors newbie

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    Mar 5, 2013
    #8
    Ok so I’m clear

    first, do the command R disk utilities and try repair.
    if that does not work then do a restore from my time machine ?

    do you think this is fixible.

    i can’t tell you how much i appreciate your help so fare



     
  9. justperry macrumors 604

    justperry

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    #9
    Yup, exactly.
     
  10. mattimoo thread starter macrumors newbie

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    Mar 5, 2013
    #10
    I can’t wait to get home from work to try it,

    i didn’t think it would let me do a recovery as i had stopped all promotions to me. does this not matter ?


     
  11. justperry macrumors 604

    justperry

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    #11
    :confused:
    promotions?

    If you meant permissions , there will be no problem, it is started off a another partition which is not affected.
     
  12. mattimoo thread starter macrumors newbie

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    Mar 5, 2013
    #12
    permissions yes sorry :)

    ok well wish me luck I’m a little scared.....

    Just had a though if anyone ever stole my mac they would just reset to factory settings,

    looks like I’ll be bolting it to the wall :)



     
  13. Weaselboy Moderator

    Weaselboy

    Staff Member

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    Location:
    California
    #13
    Try this.

    Restart your computer from the recovery partition by booting while holding command-r keys both at the same time.

    While in recovery open Disk Utility and run a permissions repair on Macintosh HD. Quit Disk Utility. (this part is not the real fix... but it is a good idea while we are here)

    Open Terminal from the Utilities menu. Type in "resetpassword" and select your user account from the drop down menu, then click the Reset button at the bottom of the window in the Reset home folder permissions and ACLs section.

    Quit the Password Utility and go back to the main recovery screen. Now restart.

    Edit: There are some screenshots here that will walk you through.
     
  14. justperry macrumors 604

    justperry

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    #14
    May I ask what the second step is for, I know reset password but is this needed?
     
  15. mattimoo thread starter macrumors newbie

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    Mar 5, 2013
    #15
    so should i also try this (then click the Reset button at the bottom of the window in the Reset home folder permissions and ACLs section.)

    Thanks




     
  16. Weaselboy Moderator

    Weaselboy

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    #16
    We are not actually resetting the PW, you just need to access this screen and click "reset" to reset permission and ACLs for the selected user. This will put home folder permissions back to default and should fix this problem.

    ACL is "access control list" and is just really a more fine grained permissions method.

    [​IMG]

    ----------

    You don't need to enter anything in the password fields on that screen. Just click the reset at the bottom right.

    I know it is confusing because you typed "resetpassword" to get here, but we are not reseting the password. You just have to type that in to get to this screen.
     
  17. justperry macrumors 604

    justperry

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    #17
    Ah, OK, I did not use Recovery yet and thought you meant password reset, good to know, was wondering how to reset Users Home Folders since Permissions does not do anything there AFAIK.

    Thanks.
     
  18. Weaselboy Moderator

    Weaselboy

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    #18
    Yeah... having to type "resetpassword" into a Terminal screen to get to a utility to fix permissions does not make any sense to me either. I don't know who at Apple designs some of these things. :)
     
  19. benwiggy macrumors 68020

    Joined:
    Jun 15, 2012
    #19
    Surely the easiest thing is just to reinstall the OS and restore your user data from Time Machine?

    As for the original cause: if your photos are in your user account, and you don't let other people log in to your account, then they can't get at your files (without resorting to more complex methods).
     
  20. mattimoo thread starter macrumors newbie

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    Mar 5, 2013
    #20
    Thanks i will try this, you have no idea how happy ill be if this works. :)





    ----------

    sorry i dont get what you mean, if i do a full restore wont this take hours ?


     
  21. Weaselboy Moderator

    Weaselboy

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    #21
    It will work. Make sure you command-q to quit the recovery session at the end. Don't just use the power button to shut down without quitting the recovery session first or the ACL repair will not occur.
     
  22. mattimoo thread starter macrumors newbie

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    Mar 5, 2013
    #22
    ok i will ready and do it word for word when it get in..

    when you say "don’t just power down or the repair will not happy" do you mean the reset won’t happen.

    sorry i just don’t want to make this problem worse.



     
  23. Weaselboy Moderator

    Weaselboy

    Staff Member

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    #23
    Correct. After you get to that panel and click the reset button, you need to command-q to actually quit everything or the reset will not happen.

    What you would not want to do is after you click the reset just hold down the power button to turn off the machine. Although even if you goofed and did this, you could just repeat it the correct way and it would work.

    Just give this link from my earlier post a good look before you start. The screens look just like on that page. You will be fine. :D
     
  24. mattimoo thread starter macrumors newbie

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    #24
    Thank you, fingers crossed for me then :)

     
  25. mattimoo thread starter macrumors newbie

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    Mar 5, 2013
    #25
    Hi Just tried it and it said reboot at the end, so i have but i just have a blnak screen any ideas ?


     

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