GUIDE: Zap PRAM, Repair Permissions, & run FSCK

Discussion in 'OS X' started by edesignuk, Sep 20, 2004.

  1. Moderator emeritus

    edesignuk

    Joined:
    Mar 25, 2002
    Location:
    London, England
    #1
    The idea for this quick GUIDE was thought up in this thread by kingjr3. Like the networking thread the idea of this is to have a quick point of reference for those common questions.


    How to Zap PRAM

    Zapping PRAM is simple, just reboot your Mac and hold down "Command(the Apple key)+Option(the Alt key)+P+R" while it is booting, when you hear the startup sound for the seond time the operation is complete, and you can release the key combination. Now just let your Mac boot as normal.

    How to Repair Permissions

    • Navigte to "Applications > Utilities", and open up "Disk Utility".

    [​IMG]

    • Select the volume where your OS resides, and hit the "Repair Disk Permissions" button.

    [​IMG]

    If you are comfortable with using the Terminal (Applications > Utilities > Terminal.app), you can also enter this command to run repair permissions - "sudo diskutil repairpermissions /" (without the quotes), just enter your password when prompted.

    [​IMG]

    How to run FSCK

    • Restart your Mac holding down "Command(the Apple key)+S" key to enter 'Single user mode'.
    • Type "fsck -f", and hit return.
    • Once complete type "reboot" and hit return to reboot you Mac back in to OS X as normal.


    If there is anything that you think is wrong here, or you think I have missed any vital steps out, please post and let me know so that I can ammend this.
     
  2. macrumors regular

    Joined:
    Jan 6, 2004
    #2
    edesignuk, can you explain why you can't just double-click on the Disk Utility application in Applications/Utilities (to repair permissions)?
     
  3. macrumors 6502a

    NusuniAdmin

    Joined:
    Nov 19, 2003
    #3
    ya i dont know why she said that...even apple does not have that

    http://docs.info.apple.com/article.html?artnum=152064
     
  4. macrumors 65816

    realityisterror

    Joined:
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    Location:
    Snellville, GA
    #4
    ... while starting up. You will hear an extra bong of the gong.

    reality
     
  5. macrumors 65816

    Elan0204

    Joined:
    Apr 16, 2002
    Location:
    Chicago, IL
    #5
    edesignuk is a he. His avatar is not him. :)

    People have said in the forums that permisions are repaired "better" if you aren't using the volume that you are repairing permissions on when you do the repair. That is why they recommend the CD method.

    However, others have said that since new files are added and permissions might be adjusted by the x.x.x (i.e. X.3.5) updates, repairing permissions without the CD is better, since these changes are not on the original install disc.
     
  6. macrumors 6502a

    NusuniAdmin

    Joined:
    Nov 19, 2003
    #6
    lol ok great to know :p
     
  7. Moderator emeritus

    yellow

    Joined:
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    Location:
    Portland, OR
    #7
    This is correct. Do not boot from the CD to repair permissions. Repairing permissions compares the permissions detailed in the BOM (Bill Of Materials) of entries in /Library/Receipts/ to those of your installed applications and OS updates. Anything that is out of whack will have it's permissions fixed. The BOM files on the CD are woefully out of date in most cases.

    As an alternative, you can repair permissions from the command line:

    sudo diskutil repairpermissions /
     
  8. Moderator emeritus

    yellow

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    #8
    ... You can let go after you hear the bong for the 4th time.
     
  9. Moderator emeritus

    yellow

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    Portland, OR
    #9
    Some might argue that you leave yourself open to a minor security risk by not specifying WHICH fsck you want to run, as in "/sbin/fsck -fy". Just typing fsck means any old fsck that appears in the SUM path first would get run instead. We're talking potential trojans here.. but this is not to say that someone couldn't replace /sbin/fsck either.
     
  10. thread starter Moderator emeritus

    edesignuk

    Joined:
    Mar 25, 2002
    Location:
    London, England
    #10
    As far as I understood it you needed to be logged in as root, or boot off the CD to have the necessary permissions to make permission changes to system files. Am I wrong then? I know I am not the only one who does this, I learnt this way of doing it from posts on this forum :confused: We need to get a definite answer on this, the Apple doc link isn't working for me btw :confused:

    As for the fsck thing, I believed -f was the correct switch to use with the command as it forces a full check regardless, this seems to make most sence to me.

    edit: OK, the link Rower provided in this thread to apples repair permisisons guide seems clear. I've changed this guide to run disk utility from within OS X, and not from the CD :)
     
  11. thread starter Moderator emeritus

    edesignuk

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    #11
  12. Moderator

    Nermal

    Staff Member

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    #12
    Now add 'at the startup tone' or similar to the end of the instructions for zapping PRAM :)
     
  13. macrumors 601

    Diatribe

    Joined:
    Jan 8, 2004
    Location:
    Back in the motherland
    #13
    Yep, you should add to the PRAM zapping that it is done while starting up. This is a newbie guide after all, isn't it? :D

    Edit: beaten to it :)
     
  14. thread starter Moderator emeritus

    edesignuk

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    Location:
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    #14
    I really thought I had said you do it while rebooting actually, I must be going crazy. Anyway, it's fixed now :)
     
  15. Moderator emeritus

    yellow

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    Portland, OR
    #15
    Can you please add this to it?
     
  16. thread starter Moderator emeritus

    edesignuk

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    #16
    Done. I'll add a screen cap when I get home to be able to do it as well.
     
  17. Moderator emeritus

    yellow

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  18. macrumors 68040

    CmdrLaForge

    Joined:
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    around the world
    #18
    Hi edesignuk,

    great idea to add another guide. The one thing I am missing, that it does just explain HOW to do the task, but does not explain WHY and WHEN.

    Could you add that ? Would be great

    Cheers
    LaForge
     
  19. thread starter Moderator emeritus

    edesignuk

    Joined:
    Mar 25, 2002
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    #19
    Problem is there are so many reasons why you might be advised to do any of these things. It's not like it's one cause that leads you do do these things.
     
  20. macrumors 6502a

    NusuniAdmin

    Joined:
    Nov 19, 2003
    #20
    *begins to write a Stickies note* edesignuk is male, not female *end note*

    sorry bout that edesignuk :p

    *sets note as a floating window*
     
  21. Moderator emeritus

    yellow

    Joined:
    Oct 21, 2003
    Location:
    Portland, OR
    #21
    I concur. However, you could dispel the myths surrounding the repairing of permissions. IMO:

    It's only necessary/advised to repair permissions after installing anything that requires an admin password. This includes, but is not limited to, system/security updates.
     
  22. macrumors 68040

    CmdrLaForge

    Joined:
    Feb 26, 2003
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    around the world
    #22
    OK, if so - then thats a problem. Even I have no idea what FSCK could be good for and I thought I know something about Macs. Obviously I don't
    :( :eek:

    Cheers
    LaForge
     
  23. macrumors G4

    wrldwzrd89

    Joined:
    Jun 6, 2003
    Location:
    Solon, OH
    #23
    CmdrLaForge - you familiar with Disk Utility and its "Repair" option for hard disks (the one that looks for and fixes directory problems)? That button is nothing more than a graphical front-end to the fsck utility, which actually checks and fixes your disk. Essentially, running fsck is equivalent to opening Disk Utility, selecting the disk you want checked, and clicking Repair.
     
  24. Moderator emeritus

    yellow

    Joined:
    Oct 21, 2003
    Location:
    Portland, OR
    #24
    Actually.. if we want to be entirely correct, the "repair disk" button is a frontend for:

    sudo diskutil repairdisk /

    Which is a Appleized version of fsck.
     
  25. macrumors G4

    wrldwzrd89

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    #25
    You're saying it's three layers deep? Disk Utility -> diskutil -> fsck instead of Disk Utility -> fsck? Didn't know that - thanks yellow.
     

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