sum

Access Single-User Mode When Locked

Once you are in single-user mode you will have root privileges and access to the entire filesystem, including password hashes.

This tutorial is much easier to do on a laptop, and some of the steps will attract some attention when in public places. So watch where you are when following this guide.

The procedure involves opening the computer, which does void the warranty.

Regardless of who’s computer this is, proceed with caution. You should know what you’re doing before removing or adding any RAM. We take absolutely no responsibility for any effects to the computers, or your warranty (it will void it).

Now that we’ve gotten that out of the way, let’s get started.

Procedure

1. Change the Amount of RAM

Change the amount of RAM inside the computer. It doesn’t matter if you add RAM or remove RAM, but the amount of RAM has to be different than the amount present when the computer was last turned off.

Be careful when handling RAM. It is very sensitive to static electricity.

2. Reset the PRAM and NVRAM

Once you have successfully changed the amount of RAM, and preferably closed the case back up, turn the computer on. Once you hear the chime signaling that the computer is turning on hold CMD+Option+P+R. Hold them down until the computer restarts and you hear the chime for a second time. Immediately after you hear this second chime release the keys, then quickly press them again. Wait until it restarts and you hear a third chime. Then repeat for a fourth time. (Note: This is resetting your computer’s PRAM and NVRAM)

3. Boot into Single-User Mode

Once you have heard the fourth chime hold CMD+S. This will boot you into single-user mode. From here you can perform whatever actions you want to do, but be careful not to change anything vital to the running of the computer.

4. Replace/Remove RAM

Turn the computer off and put the original amount of RAM back inside. This step isn’t necessary but is highly recommended.You should try to leave the computer as close to its original state as possible.

Again remember that opening up a Mac does void its warranty, and if you open up a computer in a Starbucks people are gonna give you some funny looks. Be smart about how you use this tutorial.

The contents of this guide are for educational use only. For more information, see our Disclaimer.

75 Comments

  1. KiKi

    11.20.2010

    Reply

    What exactly is RAM??? and how do you access it on a MacBook??

    • Jeff Browning

      11.20.2010

      KiKi, RAM stands for Random Access Memory, and appears in the form of “sticks”, which are computer chips that slot into the motherboard.

      If you did not know what RAM meant, I highly recommend not performing this procedure. It’s easy to kill a stick of RAM by not taking the right precautions, and removing it or placing more in without knowing what you’re doing can break your computer.

      To access the RAM on a MacBook, you have to remove the bottom of the laptop, and identify where the RAM is (differs depending on the model).

    • Basil

      11.28.2012

      its in the back of your computer.I would recommend having another computer close by.to help you

  2. BB

    11.29.2010

    Reply

    Jeff I was reading your post and I tried the hack on how to create a new administrator a dozen times. Obviously I did something wrong. After typing in all of the little codes e.g. /sbin/mount -uw /….. I pressed enter. Is that correct?

    • Jeff Browning

      12.05.2010

      @BB – Are you entering each command separately and hitting enter? You cannot enter them all in the same line and press enter, you need to execute all of them in the proper order.

  3. tea

    11.29.2010

    Reply

    I did all that but the new admin user does not recognize the other two accounts on the users folder. Can I tell the computer that those old users are actully part of the system? THanks

    • Jeff Browning

      12.05.2010

      @tea – Check your ‘System Preferences’ Accounts pane, do they show up there?

  4. BB

    11.29.2010

    Reply

    Hey Jeff I got the thing to work except all did not go according to plan. Once i typed in reboot I thought it had worked, but it took my right back to sign in screen for my computer(where you choose what user you want to log into. What happened?????

    • Jeff Browning

      12.05.2010

      @BB It looks like you haven’t properly deleted the file, and Mac OS X still thinks it’s there. Try going through the steps in the guide again and let us know how it goes.

  5. tsuki

    12.04.2010

    Reply

    eto..this doesn’t work……
    /sbin/mount -uw/
    rm /var/db/.AppleSetupDone
    it tells me there’s no such thing as rm /var/db/.AppleSetupDone
    i tried it without the rm and then it jus said permission denied….so just curious…..does this work on all macs cause i’m using a mac os x but it’s like a really old one cause it hasn’t been updated since 2004…so it’s only updated to 10.3.8?
    is there anything else i can do cause i’ve tried many things and stuff and nothing works cause it all usually ends up telling me file does not exist or permission denied…

    • Jeff Browning

      12.05.2010

      @tsuki – Your problem lies in the age of the machine. This guide only works on 10.4 and up, so it looks like you’re just below the cutoff! I’ll be sure to edit the guide soon with this information.

  6. badboy

    12.12.2010

    Reply

    Hey Jeff,
    I am a non-admin account user trying to create my account to admin. Is there any way I can transfer all my files from the non-admin to the admin then delete the non-admin? Or mabye can I make my non admin into an admin then delete the admin I created (if that made sense)?

    • Colin

      01.05.2012

      While on the admin account go into System Preferences then into Users and Groups and change your account into admin..

      im sure you have the answer allready but i was bored so i answered..

    • Jason

      01.29.2012

      badboy, you can modify your existing account to make it an admin once you have administrator access to the machine.

  7. Chris

    12.14.2010

    Reply

    I type in the very first line and get the following error messages (User names edited out for privacy)

    SMBP-1043:~ AAAAA$ dscl localhost -read /search/users/BBBBB | grep Genera tedUID | cut -cut15-
    cut: [-cf] list: illegal list value
    grep: tedUID: No such file or directory
    DS Error: -14009 (eDSUnknownNodeName)

    What is going on and what should I type to make it work?

    • Alex Galvin

      01.02.2011

      Hi Chris,
      It looks like you may have a space in the middle of GeneratedUID. It should be all one word. Try taking out the space and seeing what happens.


      Alex Galvin

  8. peter

    01.03.2011

    Reply

    I somehow find PHP much easier and simpler than Applescript. I just don’t get it.

    Can someone point me to a good tutorial? not a hello world tutorial btw

    thanks!

    pete

  9. Hi there

    02.10.2011

    Reply

    Will this void custom insurance?

    • Jeff Browning

      02.17.2011

      I’m not totally sure what you mean by “custom insurance”, but from the sounds of it, I’d look into your Terms and Conditions to see if any self repairing or repairing by somebody who is “unauthorized” is disallowed – if it is, it’ll void that.

      This procedure definitely voids your Mac’s warranty, so if the Geniuses find out, they won’t work with your computer at the Apple Store.

  10. Mat

    03.08.2011

    Reply

    Hi mate! I recently got a problem with my mac. I think it is called a kernel panic? I’m not sure. I fixed my problem using single user mode because I don’t have the installer discs with me. Anyway, after copying some texts from the site to safe user mode, I was able to run my mac again, but the problem is, the account was not an Admin account as it was supposed to be. Can you please help me with this problem? I use my mac for school. Lastly, I have tried some codes like “/sbin/mount -uw” and so on. I have actually tried this three times and now I have three accounts which are standard only. I really need your help. I have exams in two weeks. thanks a lot!

  11. Anthony !

    04.12.2011

    Reply

    Hello ! Im trying to access the admins password so i can install some games. This is my computer but i go to school on it so the school put install blocks only bypasses by the admin. So i need to make a admin account or change the password. But its seems ive tried everything ! Ive held down command +s, ive tried the dick. Nothing works. can you help please?? Im using an iMac by. the desktop

    • Jeff Browning

      04.19.2011

      Are you certain that you’re holding down CMD+S on the gray startup screen, before the Apple logo appears? Otherwise, that means they have a firmware password enabled, which can be removed by changing the amount of RAM inside the computer (a bad idea if the computer is the school’s).

  12. Pieter

    04.24.2011

    Reply

    Hey having a keyboard problem in single user mode.
    As soon I get to the the screen with white text, I’m unable to type anything with my keyboard.
    I’m using a logitech g15 but it has no problem typing in osx or in getting me to single user mode.
    Any ideas?
    Thanks.

    • Jeff Browning

      04.29.2011

      Do you have a plain-ole standard USB keyboard lying around? Most drivers are not active in Single-User Mode, even though they are in all other parts of the OS.

      See if you have one in the attic or if you could just borrow one from a friend and give that a shot.

  13. Jo

    04.28.2011

    Reply

    Hello, I can’t type AT ALL when I’m in the single user mode. I’ve tried this and it still doesn’t let me type. Help? (ps: I’m not the administrator on the computer)

    • Jeff Browning

      04.29.2011

      Hey Jo – What do you have for a keyboard? If it’s not a plain, standard USB keyboard, it might not work; most drivers aren’t active during SUM.

  14. sheia

    05.03.2011

    Reply

    do you do the same process for a desktop

    • Jeff Browning

      05.04.2011

      Yep, you just have to unscrew the bottom (if it’s an iMac) or remove the side panel (for the Mac Pro) to access the RAM.

  15. tyson

    05.09.2011

    Reply

    hey ive done this a couple of times but i found another way on the disk theres the application open firmware utility if u have administrator access you can change it or what i did was edit the resources and and made it look like a google chrome updater and got my administrator to “update google chrome”

    • tyson

      05.09.2011

      btw heres a tricky one for you i have parental controls open firmware password which means no sum no terminal no apple script editor no widgets

    • Jeff Browning

      05.09.2011

      Tyson – That’s a cool trick, but your system administrator has to fall for it.

      As for your situation, it’s pretty easy with the OS X install DVD. Pop it in, pick a language, then select “Password Reset” from the Utilities menu. You can then select an account to reset the password of, and you can even reset the root password if you select “System Administrator”, you’ll reset the root password.

      Just be careful, because with the root account, there are no safety rails. The computer will do anything that you tell it to without asking whether you’re sure or not.

  16. mike

    06.05.2011

    Reply

    Hey jeff

    I have tried this method (of removing ram to gain access to Single User Mode) but i have had zero success. When i turn the computer on there is no “chime” at any time. I have also tried using head phones.
    Can you please recommend any other ways that i may be able to gain access?

    • Jeff Browning

      06.06.2011

      Are you sure that there is a firmware password? If there isn’t one, then you should be able to simply hold CMD+S on startup to boot directly into SUM.

    • Ineluctable Square Root

      09.29.2011

      The trick is to change the amount of *working* RAM in the computer. More or less is fine, so long as it’s sufficient for the computer to boot and run. I’m guessing the poster removed too much RAM, leaving the computer in a non-bootable state.

  17. Jonathan

    07.12.2011

    Reply

    Changing out the RAM does not void the Apple Warranty.

    • Greg

      10.28.2011

      More generally, there has never been any Mac for which it’s a true statement that opening it voids the warranty. There are certain things you might do once you’ve got it open that will. But simply opening it, and changing around things like drives or RAM is, and always has been, completely fine.

  18. Makalani

    07.29.2011

    Reply

    Hi Jeff,
    My problem is this…my son did something to my iMac 10.6 which caused it to freeze. So I rebooted with my disk and everything works fine except my account turned to standard and I cannot download anything. So I tried doing what you have written, but I cannot type in single user mode. I am using my standard usb keyboard. Is there anyway around this? I really need to download a few things.
    Thanks so much!

    • Jeff Browning

      07.31.2011

      You can create another Administrator account using the install disk, and from that account, change your account back into an administrator.

    • cece

      08.15.2011

      Hi Jeff-

      Could I create another Administrator’s account temporarily then delete it to erase my tracks?

  19. Deepan

    09.13.2011

    Reply

    hello im trying to do this on a macbook from 2009 i have not started the process but in the first step it says i need to change the amount of ram? so im supposed to buy ram? because the computer has 2gb ram installed, i have 2 1gb ram sticks laying around can i just insert those into the computer? or does it have to be a quantity higher than 2gb?

  20. VWR

    09.16.2011

    Reply

    Hola!

    Got into SUM no prob. At prompt (root#) typed: /sbin/mount -uw / then pressed enter
    At second prompt (also root#) typed: rm /var/db/ .applesetupdone and pressed enter again
    It tells me .applesetupdone does not exist. Trying this on MacBook version 10.6.8
    Needless to say, I have been unable to create a second admin account. Have checked Accounts in System Preferences just to make sure. No luck! Suggestions?

  21. Rahul

    09.27.2011

    Reply

    hello sir…
    sir,i want to view the admin account password through the limited account..
    is it possible????
    remember i don’t want to change password simply i just want to see that password…
    I’m I.T executive that’s why i need that trick…

    • Jeff Browning

      10.23.2011

      If you’re an I.T. executive than I feel like you would have the administrator account password…

      and no, it’s not possible, you need root access to decrypt passwords.

  22. Calum

    11.15.2011

    Reply

    Hey Jeff,

    I want to do this on my Macbook Pro but I need to know a couple of things before I try it…

    Does it work on a Macbook Pro? (I know where the RAM is)

    Will all my accounts still be there? (Non-admin and admin accounts)

    And lastly, will my files still be there on my non-admin account?

    Thanks, any help will be greatly appreciated… Have a good one :D

  23. brian

    11.22.2011

    Reply

    since there is two sticks of RAM can i take out one stick and leave it out during the single user mode, or do i have to place another stick of different memory to do that?

  24. lee harvey

    11.25.2011

    Reply

    Hi Jeff. i’m really new to the Mac System, but quite well versed in pc’s. i aqquired a imac but the person i got it from couldnt tell me anything about it.. after some googleing i discovered that i could create a 2nd admin account via the single user mode. however, when i try to enter SUM it says
    Singleuser Boot — fsck not done
    Root device is mounted read – only
    If you want to make modifications to files:

    /sbin/fsck -fy
    /sbin/mount -uw /

    If you wish to boot the system:
    exit

    -sh-3.20

    when i enter /sbin/fsck -fy command it says
    ** /dev/rdisk0s2
    ** Root file system
    Executing fsck_hfs (version diskdev_cmds-491.6.3).
    ** Checking journaled HFS Plus volume.

    etc etc

    ** The volume Macintosh HD appears to be OK.

    -sh-3.2#

    why is it returning to -sh-3.2# if i’m correct it should be returning me to a #ROOT
    ive tried mount -uw / and rm /var/db/.applesetupdone but when i restart the computer it just hangs on the Apple screen

    Please can you help

    thankyou for saving my sanity

    lee

  25. Dexter

    12.09.2011

    Reply

    I have tried this on a mac mini, model 2006, but I do not have a chime upon startup? What is wrong and how do I fix this.

  26. Mailon

    12.10.2011

    Reply

    Jeff, I work for an AASP and removing RAM definitely does not void Apple’s warranty. In fact, Apple even has a support page that instructs people how to remove/upgrade their RAM. Just thought this should be pointed out. Apple is usually pretty lenient with their warranty. For instance, if you upgrade your HDD and your optical drive later stops working, Apple will 99.99% of the time still honor the warranty. The only thing that won’t be covered at that point is the new HDD. If you for some reason you replace everything in your computer then Apple won’t work on it, but basic stuff like RAM does not affect the warranty.

  27. Miller

    12.11.2011

    Reply

    After you have opened the computer up and taken out 1 stick of RAM and held down the right keys to reset the PRAM and NVRAM, can I put the original amount of RAM back in and boot into SUM? Do I have to boot into SUM with a stick of RAM missing?

  28. Daniel

    12.13.2011

    Reply

    I tried doing it but it didn’t work. I replaced the RAM successfully, started it up and when I heard the chime I pressed CMD+Option+P+R and held them down; nothing happened other then the usual start-up process. So I tried it again, and again, and again. I have tried it twelve times now, and it hasn’t shown any signs of working. What could be going wrong?

    • Daniel

      12.14.2011

      Hmm… Single-User mode is blocked somehow, but possibly not by a password. My computer just doesn’t do anything when I try to access it. It does exactly the same with the commands for resetting the NVRAM and PRAM. I guarantee you it isn’t to do with how I am doing it either. I have tried every way, and watched videos of other people doing it too.

      Have you any bright ideas of what I could do?

      Also, there is another person, going by the name of Steve, that I stumbled across on the forums with an almost identical problem. I am not alone.

  29. Dexter

    12.13.2011

    Reply

    Hello
    I use a Mac Mini, 2006, I know that the RAM is working, but the mac even though the working RAM is changed, I still receive no startup noise ( Which I actually have not for around a Year now ) and I am still not able to boot into SUM. I am using 1.5 Gigs of SDRAM, although I do not know if that would have a slight if any effect on the custom booting on my Mac.
    Regards

  30. Luke

    12.18.2011

    Reply

    Hello,
    I have changed the amount of RAM, but first there is no gray start up screen, and second I have tried resetting the PRAM etc. but as I am holding down Command + Option + P + R it does nothing.

  31. jkneb

    12.25.2011

    Reply

    Hi guys,

    Maybe you can help me. My MacBook Pro Hard Drive is dead. It just doesn’t boot, the gray screen turns to a wonderfull http://goo.gl/xVxw8 invalid sign in the middle of the screen.

    I went to the Apple Store to see a “tech guy”… they say it’s too hard for them and the only option they have is to simply replace the HD by a new one BUT then they will not give me back my corrupted HD :(
    I’ll try myself before giving up.

    Ok some datas :
    • Can’t boot in normal mode (the gray screen with Apple logo and the spinning loader).
    • Can’t boot in safe mode. (same)
    • CAN boot in single user mode. (yeah!)
    • After a moment more or less fast the HD appears to not be present anymore (in SUM)
    • In fact I have approximatively 10 minutes max in SUM to access my datas.

    First question, I can see that SUM is read only, so is it possible to transfer files from the HD to another exernal drive inside the 10 minutes window?
    Second question, how do I mount an external drive in SUM?

    Hope you can help me with that :)
    Cheers & merry christmas
    Julien

  32. b

    01.01.2012

    Reply

    Hello,
    I have a 2009 MacBook. I removed the memory (http://support.apple.com/kb/HT1651#link3) and then followed the next step of holding down Command+Option+P+R after the chime and then I am brought back to the login screen. I then restarted the computer and followed the steps of holding down Command+Option+P+R at the chime…. and then the login screen appears. I did this 3 times with the memory out and have the same result. Please, oh please help me troubleshoot this.
    Thank you

  33. sonia

    01.07.2012

    Reply

    allo le macbook de ma fille est bloqué elle a changer le style d ecriture sur son mac et n est plus capable d ecrire son nom utilisateur et son mot de passe avec cette ecriture speciale car elle fesait copier coller a chaque fois mais ca ne marche pu on connait le nom utilisateur et mot de passe mais ca ne fonctionne plus quoi faire ??

  34. peter

    01.27.2012

    Reply

    jeff im so confused right now im on a school computer and i do not have the adinisrator password or
    name

    what the hack do i do?

  35. John

    01.28.2012

    Reply

    You don’t have to press CMD+Option+P+R four times, have you? I thought 1 time was enough.

  36. James

    03.05.2012

    Reply

    Hi there,

    I was able to go into single user mode to create an admin account. However, my father has done something so that whenever I hold down CMD + S, it goes into single user mode, loads everything and then some additional code is typed at the end very very quickly and the mac reboots.

    How can I fix this so that I can get back into single user mode?

    I’m almost 20 years old and my dad feels the need to limit the computer usage to 2 hours a day. This isn’t viable when I’m in my final year of school and have a hell of a lot of work to do.

    A quick reply would be appreciated

    Thanks!

  37. Austin

    03.27.2012

    Reply

    hey, is there another way to get into the single user mode without changing the RAM?

  38. Gevin

    04.01.2012

    Reply

    i see the start up screen but i took out ram and followed the step but it logins in to the administer account it is on auto-login the problem it i cannot change thing i need a password to do anything

  39. Souf

    04.21.2012

    Reply

    And how can i do it for a MacBook Air please, if they asked for a 4 numbers pin code?? they also required a pass for the commd+option+ P+ R

  40. Nathaniel

    04.28.2012

    Reply

    Hi,
    I have 2 questions:
    1. How can I tell if a firmware password is installed, and
    2. What should I do if I am unable to change the RAM in the computer and there is a firmware password installed?

    Thanks a lot,
    Nathaniel

  41. Paul

    05.13.2012

    Reply

    So I bought a MacBook from a school that is running 10.6.8. After changing the ram and following all the instructions when I go into single user it asks for a key. Is there anything I can do to get pass this?

  42. frankii

    06.03.2012

    Reply

    every time i get in single user mode it just reboots? any help?

  43. Mike

    07.03.2012

    Reply

    Hello, I have tried changing RAM, and putting cover back on, then holding the keys after chime, and i get this lock on the screen. It just shows a lock and does not restart. Any thoughts?

  44. Jenna

    07.06.2012

    Reply

    when you do this? does this reboot the whole computer making it start over from the beginning when you first bought it?

  45. Cristian Leon

    07.29.2012

    Reply

    it really works for me thanx a lot i have an imac and it was blobked with users password so this really helpd me thanx. :-)

  46. aric

    09.26.2012

    Reply

    hey i have tried this and i cant get it to work i have a macbook and im trying to get through the admin security i got this laptop from my school a couple years ago and when i went back becuse of these locks the i.t department doesnt work their anymore i guess they all left so nobody down there can help me please what do i do i can get into single user mode but then what?

  47. Steven

    09.27.2012

    Reply

    Can you make a tutorial on cracking wpa2 passwords?

  48. Paul

    11.06.2012

    Reply

    After booting into SUM i get

    lock: /dev/console on . timeout in 86343727 minutes
    time now is Tue Jun 26 21:13:21 cdt 2001
    key:

    Why is this coming up and how do i get around it?
    Please respond ASAP and thank you

  49. geedee

    11.11.2012

    Reply

    can this be done on macbook air (2011) ive tried everything please . any advice would be appreciated

  50. Jarle

    12.02.2012

    Reply

    Hi Jeff, my 2 year old Macbook Air won’t log me in cause I think the keyboard driver might be corrupted or something. It says wrong password, but I’m 100% sure it’s correct. So when in single-user mode, all the letters are uppercase, not able to switch to lowercase, even the numbers are not there (like when enter “5″ i got “%”. Because of this i can’t do nothing in single-user, like changing passwords. Tried the reset NVRAM as well, but it won’t recongize the keyboard inputs…Any idea?

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