Terminology question: "booting as root" vs. "booting in single user mode"

Terminology question: "booting as root" vs. "booting in single user mode". Are these terms interchangeable, or is there a subtle or not-so-subtle difference? (Obviously something I don't do often.)
Thanks in advance.

Boot to Single user allows root access.
It isn't "booting to root" as in Linux, but I think is as close as it gets.
You can enable root from a normal boot:
http://www.youtube.com/watch?v=Y-JEpDi-cME
Interesting read:
http://www.securemac.com/macosxsingleuser.php
This is fun:
http://osxdaily.com/2007/01/22/what-happens-in-the-mac-os-x-boot-process/

Similar Messages

Won't boot normally or in recovery and single user mode, safe mode hangs up halfway

iMac locked up with visual glitches while playing the Mac beta client of League of Legends. Had to force a shutdown by holding the power button. Now it won't boot; after the Apple logo and spinning wheel I just get a white screen. I tried launching in recovery mode, that didn't work. Then I tried safe mode; the bar filled a little over half and then nothing but white screen. I was able to boot single user mode once; ran fsck -fy and rebooted, still white screen. Now I can't get back to single user mode. I booted with command option P R to reset the NVRAM and got the second chime, but still nothing.
Luckily all my important files are in the cloud, but I'm really hoping my computer isn't completely dead. I haven't had any issues in the past. I've even been playing LoL for over a month with no issues, until now when I tried to play the newer game types, Dominion and ARAM; both caused visual glitches forcing shutdowns. I was able to restart my computer with no problem after the first two visual glitches, but after the last one I am stuck at the white screen as I described above.
Thanks in advance for your help!

I'd bet the drive is damaged. You could try reformatting if possible. Again, you are booting from the Recovery-10.8.2 disk if you can. If you can't, then you will need to use the installer disc that came with the computer.
Install or Reinstall Lion/Mountain Lion from Scratch
Be sure you backup your files to an external drive or second internal drive because the following procedure will remove everything from the hard drive.
Boot to the Recovery HD:
Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.
Erase the hard drive:
1. Select Disk Utility from the main menu and click on the Continue button.
2. After DU loads select your startup volume (usually Macintosh HD) from the
      left side list. Click on the Erase tab in the DU main window.
3. Set the format type to Mac OS Extended (Journaled.) Optionally, click on
        the Security button and set the Zero Data option to one-pass. Click on
      the Erase button and wait until the process has completed.
4. Quit DU and return to the main menu.
Reinstall Lion/Mountain Lion: Select Reinstall Lion/Mountain Lion and click on the Install button.
Note: You will need an active Internet connection. I suggest using Ethernet if possible
            because it is three times faster than wireless.

Macbook won't boot after Airport update, stuck in single user mode

Wasn't sure what forum to put this in, so I'll start here. After re-imaging student machines from the server, for some reason the new Macbooks no longer recognize they have an airport card. On another machine I download the appropriate Airport software, copy to thumbdrive, and install on student laptop. After required reboot, the Macbook refuses to boot into OS X- I get the grey apple logo, spinning gear, then drops to what appears to be single user mode, with the exception that it seems to be "refreshing" itself constantly with messages appearing for brief moments (too fast to read). It cycles so fast that I can't type anything before it is gone again. If I purposely boot into single user mode, everything behaves as normal, if I mount as fire-wire drive, everything looks good. But I can't get into OS X. Before I brick more student machines, have any ideas?

Some added info, i CAN boot the bricked machine into Safe mode, but at reboot I get stuck in the same cycle again.
Oh, and in SafeBoot, the Macbook still tells me that no Airport card is installed, even though I know it does (and it's not knocked loose or anything).....

2012 Macbook Pro won't boot from CD and freezes in single user mode

I'm rebuilding a macbook pro. Everyting was fine until I tried to install Snow Leopard from the disk. It goes to the Apple symbol no spinning wheel and you can hear the drive working for a few seconds but then stops. I've also tried booting to sinlge user mode but it just freezes after Loading System\Library\Caches\com.apple.kext.cahces\Startup\Extensions.
I've tried resetting the PRAM as well.

If you have a 2012 MacBook Pro, you can't install Snow Leopard because it's not compatible, so it's normal that you can't start OS X.
Now, you have to install OS X Lion or Mountain Lion again. Hold Command, Option (Alt) and R keys while your Mac is starting to start into OS X Recovery, and reinstall OS X. After reinstalling OS X, you will be able to use your computer.
You can't run an older OS X version than the one that came with your computer, because of some reasons:
1. The hardware isn't compatible.
2. The firmware restricts the installation of older versions on the computer.
3. It's illegal: Apple doesn't allow you to install an older OS X version than the one that came with your computer, and it doesn't mind the method you use (a "normal" installation or a virtual machine)

Booting in Single User Mode

Hello All,
Just want to prepare ahead of time for possible server-down cases where a drive fails etc. What I want to do is find out a bit more about how the boot sequence is completed.
If for example the primary boot partition was to become corrupted, is there an easy way to boot from the cdrom and enter single-user mode? From there I could mount a drive, bring up the nic, and transfer files etc, as needed.
Normally with the bootprom on Sun hardware the stop-a then boot -s cdrom would work. What's the comparable command for Solaris 8 x86?
Thanks,
Mike

This link might be helpful.
http://sun.pmbc.com/faq/7.html

Impossible to boot MacBook Pro Retina ! impossible to start in single user mode, Openfirmware password set, but safari works!

I have got a Macbook pro retina.
I have done 2 partitions on the SSD drive. 1 for the OS and 1 for the user (with a kind of ln -s /Home/myself /Volume/Part2/myself
I was watching a movie (with VLC) in full screen for a while and I wanted to escape. Impossible, and impossible to reboot.
When I start, I have a directory with a question mark.
I have a Open firmware passwords set (that I remember).
I cannot reset PRAM. (I can not change the RAM amount inside the commuter as this is a retina model)
I cannot start in verbose mode.
I can choose a disk to boot. I see only the OS drive and not the user partition, and no 'recovery partition'. It seems that i need to do a fsck -yff on the user partition but how ?
I can start the OS partition, and i can choose 'guess' or 'myself'. If i choose myself, I have an error message :'there is a error, the session can not start'. If I start with the guess account, I restart, and then I can browse the internet with safari (this is how I am writing this text!)
=> How can i repair the partition ? (open a terminal, boot in single user mode ...?)
best regards.

Actually, the recovery partition was there, but was not shown as my user partition. I have seen that reseting the PRAM and changing the ram could remove the open firemware password. So i have turn the computer on until the battery was empty. Then I boot about 20 times, and unplug the power supply after few seconds at different step of the booting pricess. At last, the screen default resolution when booting changed, I undertood that i succeeded, and I was able to enter.
Then I boot in single user mode, removed the open firmware password, activated the root user, and everything was fine now !

Can you run a bash script on boot in single user mode

Hey guys quick question.
Is it possible to run a bash script on boot in single user mode.
I can create a file and dump it on the root hd.
Let's call it repair.
I can then boot to single user mode and run it by typing /repair.
But I want it to do it automatically.
Every time I go into my machines that I clean for my job. I have to run sbin/fsck -fy
Then I have to mount the drive and then remove all cache files, then reboot the machines.
I would like to automate this by just holding command s and then moving to the next computer.
There must be some sort of boot daemon somewhere.
Please help.
Sincerely,
John

Have you seen Applejack?
http://applejack.sourceforge.net/
It doesn't start automtically, but does cleanup.
Robert

Single-User Mode Copying Files/System Does not Boot Past Apple Logo Screen

I have a Macbook 2.0GHZ, 2GB RAM, that recently tried to download a secuirty and keynot update. Following the download the system will no longer boot past the Apple Logo Screen with the spinning wheel. I do not have access to a OS disk yet or to a firewire cable either. I've have seen posts from others that describe how to use traget disk mode to reinstall the secuirty update manually and then they can boot their computer. Safe mode will not work. I did boot into single-user mode and run the disk utility there and it says my HD is OK. Since I do not have a firewire or an OS Disk, I am wondering if there is a way to copy those files i need to a USB pen stick then install them onto the computer via single-user mode, considering this is the only way I can boot and manipulate the machine at this time. If this is not possible please let me know so I can find a way to scrounge up a firewire cable or disk. Thank you in advance for any assistance.
Ted K

Thanks to Limnos and BDAqua I know you guys have helped others with these kind of problems from the other posts I read. I just want to list what I did exactly in case anyone wants to try to do this with a usb drive or does not have access to a boot disk or firewire cable.
1: Install security update on a pen drive
2: Boot in single user mode, CMD-S on startup
3: /sbin/mount -uw /
4: mkdir /Volumes/usb (usb can be any name, name of usb drive or anything you want)
5: ls /dev (you need to get the drive listing for the usb drive to mount it appropriately, it should be disk#s# but this is close to what the HD and Cd drives are listed as so you may need to list once before you put the usb stick in and once ater. I had issues inserting the usb drive in single-user mode and it would freeze up the root drive)
6: /sbin/mount_msdos /dev/disk1s1 /Volumes/usb (this mounts the usb drive, i had to use msdos because of how my usb drive was formatted, you may need to check your usb drive format, hfs is the apple format for usb drives but it did not work for me)
7: cp /Volumes/usb/SecUpd2009-001Intel.dmg (this copies the files from the usb drive to the root drivel, at this point you no longer need the usb drive)
8: hdiutil mount /SecUpd2009-001Intel.dmg (this mounts the disk image)
9: cd /Volumes/"Security Update 2009-001" (after i mounted the image this is how it appeared in the Volumes directory, you might need to do ls /Volumes to get the name, the quotes are important to get the whole file directory changed)
10: installer -pkg SecUpd2009-001Intel.pkg -target / (this installs the acutal update, i used the SecUpd2009-001Intel.pkg and it worked though I think you might be able to use "Security Update 2009-001" with quotes as well.)
11: reboot
i hope this helps anyone looking to do this. Thanks again to those who helpes and all the other posts that had information that helped me identify and then fix my issue! I still love my mac.

Getting a "key" prompt when booting up in single user mode!!

I bought my used macbook pro about a week ago without the original cd's and manuals. I installed the boot camp package but rebooted without creating the drivers disk to do this later. When my macbook boots up now it passes the apple icon with the twirling round arrow, then it stays at the Mac OS X box forever. How do I fix this without the tiger CD.
I have tried booting up in single user mode and it takes me to a "key" prompt. Anything i type does not come up. I read the troubleshooting and it sayd that it should through me to a # sign instead so i can perform a "fsck --y" funtion.
Please help restore my Macbook!!
CM

I waited 15min at the key prompt when booting in single user mode and it unlocked the command prompt.
I guess it's some sort of security feature for the root.

IMac G5 won't boot in normal and safe mode, but will from single-user mode

Hello everyone,
I'm quite new here, so I try to do my best if you have a question.
Yesterday, someone nearby me had a iMac G5 (Powermac8,1), and he sayd, that the computer sometimes will boot, sometimes not.
I did test it, I thought it was running fine, but when I played some music in iTunes, it was stuck on 9 seconds, and crashed (with a kernel panic). The guy also sayd, that there was nothing important on the computer, so a clean install was fine.
Now, the problem is, that it will not boot in normal mode (without anything pressed on boot), also it won't in safe mode (shift-boot), but it will, when I enter single-user mode, mount the hard drive and exit from single-user mode so it will go futher on booting. Sometimes it will not, and immediately gives you a kernel panic in single-user mode, but it will 90 percent of the time.
Then you've got another problem: when it's running in the normal desktop from single-user mode, it'll be stuck after some time again. If I look into the Kernel Panic file created, most times it's because of Spotlight indexing, so I disabled that.
He also gave me the disks (Apple Hardware Test and Extra Applications, and iMac G5 Mac OS X Install Disks 1-3) that came with the Mac. He sayd that I could use them, but I think he didn't test out the SuperDrive, because when I insert a disk, it will try to read, but it will make 2 same sounds, and quits after 10 tries, when it will spit the cd out. Also normal (audio) disks.
Also, I must hurry with the commands for mounting and exiting in single-user mode, or it will just not boot.
In all cases, after 30-45 seconds from pressing the power button, the fan will start blowing at full speed, and it will stop after the exit command in Single-user mode. That's weird.
I can't do anything with the SuperDrive, I can't normally boot in Mac OS X except for Single-user mode (but I don't think he would like to do that every time the computer boots up), and I have very limited time when Mac OS X arrived on the desktop.
When booting in Verbose mode, it will be stuck on this:
AppleSMU::PMU vers = 0x000d004c, SPU vers = 0x15, SDB vers = 0x01,
(and sometimes ends with a kernel crash by fsck_hfs)
Things I've tried (without any success):
- /sbin/fsck -fy (in single-user mode)
- Disabling Spotlight and mds
If you want some more information, feel free to ask!
Greetings
-MrYoranimo
PS: My main language is Dutch, so my English can be bad at some points.

Thank you for your support! This reply is a little bit late, because I was to the camping this weekend.
The only thing I sure do know, is that the iMac has a bad SuperDrive. That's one problem, but I don't really wanna use it, and you fix everything by Single-user mode and when I get to the desktop to test things and change stuff in the Preference Panes.
What also came to my mind was that there also is a problem with the videocard (driver), because sometimes when I boot into Single-user mode, I can see some white pixels which aren't supposed to be there. And when booting from SUM you can see that some of the colors are different and there are weird patterns on the screen.
I also tried to setup a NetBoot server on this computer (MacBook Mid 2010) with just Lion 10.7.4 on it, but I'm not that expert and I didn't really find the good posts on the Internet, although I tried it with the Server applications and both Server applications and DeployStudio. But I didn't succeed.
I don't really like buying a new FireWire hard disk or external FireWire dvd reader/writer, except if it has USB support, because my MacBook doesn't support FireWire, and I really wanna make use of it then.
If I know more or have fixed it, I will surely post again here with what I did to fix it (if no one else has posted here already ).

How to mount USB & CDROM drives from single user mode - Solaris boot disk?

Hi All,
I need to carry out ufsrestore on a single newly replaced system disk (no redundancy / mirroring) from either USB or CDROM drives from the following steps:
( i ) GRUB => e, e, cdrom –s, Enter, b (boot from Solaris 10 x86 media).
( ii ) Choose menu 1 for Install Solaris Interactive Mode to reach single user mode.Below are the commands that I have tried in single user mode without success:
mount –r –F pcfs /dev/dsk/c1t0d0p0 /cdrom (after unmount Solaris CD)
mount: /dev/dsk/c1t0d0p0 is not a DOS filesystem.
svcadm –v enable smserver
svcadm: Pattern ‘smserver’ doesn’t match any instances
svcadm enable autofs
svcadm: Pattern ‘autofs’ doesn’t match any instances
devfsadm
devfsadm: mkdir failed for /dev 0s1ed: Read-only file system
mkdir /mnt
mkdir: Failed to make directory “/mnt”; Read-only file systemPart of the problem is due to the current READ ONLY filesystems which does not allow the creation of mount point such as /mnt.
I have been able to create both / root (/dev/dsk/c1t0d0s0) and /export/home (/dev/dsk/c1t0d0s0) filesystems with newfs that are awaiting for restore using ufsrestore.
The only option I am left with is to attach a secondary disk to install Solaris 10 on either of them before bring the system to multi-user mode so that service such as volmgt, autofs, volfs are available to access USB & CDROM drives.
Any suggestion on how to resolve this issue?
Many thanks,
Jack

Hi JKGN,
Is the directory a located under the root filesystem. ie /a? Are there any other mount point for say USB drive as well? I am not in a position to try it out right now but will get back
to you soon on whether /a exist or not.
Btw, the last thing I managed to do on this system at the time was added a secondary 1TB internal disk with the intention to restore both / and /export/home data onto this disk while
making use of all the disk device management services such as the following services only available in a fully installed Solaris system (both single & multi-user modes) installed on the
primary disk:
# svcs smserver
STATE          STIME    FMRI
online         Jun_08   svc:/network/rpc/smserver:default
# svcs autofs
STATE          STIME    FMRI
online         Jun_08   svc:/system/filesystem/autofs:default
# devfsadm
# iostat -En
c1t0d0           Soft Errors: 0 Hard Errors: 0 Transport Errors: 0
Vendor: ATA      Product: SAMSUNG HD321KJ Revision: 0-11 Serial No:
Size: 320.07GB <320072932864 bytes>
Media Error: 0 Device Not Ready: 0 No Device: 0 Recoverable: 0
Illegal Request: 41 Predictive Failure Analysis: 0
c0t0d0           Soft Errors: 0 Hard Errors: 5 Transport Errors: 0
Vendor: PHILIPS Product: DVD+-RW DVD8801 Revision: AD21 Serial
Size: 17.54GB <17538875392 bytes>
Media Error: 0 Device Not Ready: 5 No Device: 0 Recoverable: 0
Illegal Request: 10 Predictive Failure Analysis: 0
c2t0d0           Soft Errors: 0 Hard Errors: 0 Transport Errors: 0
Vendor: JetFlash Product: Transcend 16GB   Revision: 1100 Serial No:
Size: 0.00GB <0 bytes>
Media Error: 0 Device Not Ready: 0 No Device: 0 Recoverable: 0
Illegal Request: 7 Predictive Failure Analysis: 0
# rmformat
Looking for devices...
     1. Volmgt Node: /vol/dev/aliases/cdrom0
        Logical Node: /dev/rdsk/c0t0d0s2
        Physical Node: /pci@0,0/pci-ide@1f,1/ide@0/sd@0,0
        Connected Device: PHILIPS DVD+-RW DVD8801 AD21
        Device Type: DVD Reader/WriterHowever, I was disappointed that "iostat -En" has not found the secondary disk (1 TB) even though it was available earlier, for Solaris installation as the only disk on the same system.
As a result, I am left with no option but the need to rebuild this system with only a single primary disk while in single user mode. However, the single user mode that I am in is the
one from Solaris installation disk with restrictive (_cannot create folder for mount point or running disk management utilities_) capability such as those services just covered, compared to one from a completed Solaris installation system with full access to all filesystems and utilities / commands in general.
I would very much value your assistance on how to mount both CD & USB in this restrictive limited Read Only OS (assume that it is running from memory) in order to get complete access to
the blank primary disk so that full restore with ufsrestore could take place.
Thanks in advance,
Jack
Edited by: 797805 on 9/06/2012 04:15

How do I mount an external Firewire HD when booting into single user mode?

Hi,
How can I mount an external Firewire Harddisk from the Darwin Console, once I have booted into single user mode?
I'm trying to make a backup of all my files and then re-install my iMac G5 since it doesn't start the GUI anymore and I haven't gotten any responses to my question here: http://discussions.apple.com/thread.jspa?threadID=1104762&tstart=0
Thanks,
Torsten

ok, I executed the following commands:
/sbin/fsck -fy
/usr/libexec/registermach_bootstrapservers /etc/mach_init.d
autodiskmount
There were two messages:
UniNEnet: Ethernet address 00:14:51:32:19:b8
and
Aug 29 20:55:29 launchd: server 2e3b in bootstrap 1103 uid 0: "/usr/sbin/lookupd"[16]: exited abnormally: Hangup
I don't know whether this has anything to do with the commands I entered.
And since I don't know what the volume name for the external Firewire HD is, I typed
ls -l /Volumes
but the only volume that is being listed there is my iMac's internal HD.
What should I do next?
Thx!

Screen resolution at boot time and in single user mode?

Hello!
I remember back in 10.3.8 or earlier my Mac booted right away in 1280 by 1024 pixels screen resolution, thus avoiding the video mode change when showing the progress bar.
I didn't manage to get it back to work this way.
Reset NVRAM ( a zillion times!) didn't help, nor did setting the screen mode from the admin or root account.
I'd really like to have it back!
It's no fun working in single user mode on 640 by 480.
I know this has been working with the original ATI Rage 128 and with the Radeon 7000 PCI I built in 3 years ago.
Any ideas?
Gerhard
Powermac G3 b/w Rev. B Mac OS X (10.4.7) RAM: 896 MB

Not sure if this is related enough, but I just wrestled trying to restore from time machine too, trying to reinstall 10.5.8 after putting a new HD in my MBP, 2006 vintage.
That took sooooo long to get back to where I was before swapping disks; what did the trick was ordering a free copy of Snow Leopard install disk (free due to Apple trying to push people from idisk to icloud) which was rushed FedEx (yay) and which allowed me to access Time Machine where my ancient original OSX install disk had not.
And all it took was 2 weeks of cursing!

Unable to boot from cdrom in single user mode

I have lost the root password for solaris 9.So, I tried booting the system with solaris 8 CD in single user mode(i.e, at ok prompt, boot cdrom -s)
But I get the following error.
rebooting with command :boot cdrom -s
boot device :/pci@1e,600000/ide@d/cdrom@0,0:f file and args -s
boot:cannot open kernel/sparcv9/unix
Enter filename:[kernel/sparcv9/unix]:
Please let me know why is this error?.Is it becos the CD is corrupted?

Also, the particular Solaris 8 you've chosen could be a distribution that's too old for your particular computer's design.
For example, a Sunfire V440 would need Solaris 8 HW 7/03 or newer.
http://sunsolve.sun.com/handbook_pub/Systems/SunFireV440/Sun FireV440.html
Solaris 8 HW 2/02 would not work.
What model system, and what version Solaris are you trying to use?

Help needed: Lion boots only in single user mode after a kasperksy unsuccefull installation

Hello everyboby,
I used to be a Sun Solaris sysadmin with root privileges, but I can't fix the Macbook of my girlfriend...
WHAT I WISHED:
I wished I could restore the boot INI/config files of a MacBook (the old one, made of white plastic, not the pro, made of "steel"), so that Lion started at boot, like it used to do, before a "fatal" kasperky installation.
WHAT HAPPENS:
the macbook plays the chord, shows the Apple logo, seems to load the OS (Lion) and then switches to graphic mode, BUT the desktop (is "desktop" the name of the screen of the operating system, once it's fully started, like on a PC?) doesn't appear, only a grey screen, then nothing happens.
I guess that probably Lion is fully running under the grey screen, but without the screen/video been correctly setup, I cannot interact with the notebook.
I CAN boot in single user mode, mount the file system in writing mode and read and write the disk.
WHAT HAPPENED:
my girlfriend upgraded to Lion from Snow Leopard and used the notebook for a while (one month?), then she decided to upgrade kaspersky, but the installation failed somehow and now the notebook is stuck.
WHAT I TRIED TO DO:
- I read this: http://developer.apple.com/library/mac/#documentation/MacOSX/Conceptual/BPSystem Startup/Chapters/CustomLogin.html#//apple_ref/doc/uid/10000172i-SW10-BAJCGEGG
- and that: http://developer.apple.com/library/mac/#documentation/Darwin/Reference/ManPages/ man5/launchd.conf.5.html#//apple_ref/doc/man/5/launchd.conf
- and removed from the disk all the folders and files dealing with startup items AND kaspersky, but nothing changed: at boot the grey screen appears and Lion's interface is not loaded (or if it is, it's not shown).
- then I looked for some logs, found the kernel's one and found something that looks like an error message dealing with video inizialization... So, it really seems something is not working at video level.
WHAT I AM ASKING YOU:
some help, please... : is there anybody that can give me some specific advice on how the boot is done on a macbook with Lion? Are there some INI files I can copy into the macbook, so that it starts in grphic mode?
whatever...
thank you in advance!
Dario

Linc Davis wrote:
I used to be a Sun Solaris sysadmin...
Then you backed up
I didn't: it's my girlfriend's notebook and she not using a timemachine external disk. She did all by herself

Terminology question: "booting as root" vs. "booting in single user mode"

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