Apple Jack Helps Repair Permissions and So Much More!

AppleJack applejack.png

In My previous post about repairing permissions I explained how to do this from inside the Os using Disk Utility. There is a command line user interface for Mac OS X that provides a simplified interface for single user mode system repairs. It is called AppleJack. YOU MUST RUN IT IN SINGLE USER MODE. To Get to Single User Mode you have to restart the computer and Hit the Command and “S” key at the same time prior to the Start up sound and the Apple appears on the screen. Below you will find excerpts from the AppleJack website about their application.

Download AppleJack

AppleJack is a user friendly troubleshooting assistant for Mac OS X. With AppleJack you can troubleshoot a computer even if you can’t load the GUI, or don’t have a startup CD handy. AppleJack runs in Single User Mode and is menu-based for ease of use.

Using AppleJack, you can repair your disk, repair permissions, validate the system’s preference files, and get rid of possibly corrupted cache files. In most cases, these operations can help get your machine back on track. The important thing is that you don’t need another startup disk with you. All you need to do is restart in Single User Mode (SUM), by holding down the command and s keys at startup, and then typing applejack, or applejack auto (which will run through all the tasks automatically), or applejack auto restart (which will also restart the computer automatically at the end of the process). has compiled a list of user experiences with AppleJack which might help you evaluate its usefulness to you. Thanks guys!

Dan Frakes has written a nice summary of the benefits and drawbacks to AppleJack for It’s thorough and much better written than anything I could have done.
Getting Help

Please read the ReadMe.rtf file which comes with the AppleJack distribution. Or, if you’ve already installed AppleJack, just type ‘man applejack’ in a terminal window. Both documents should cover the basics of what you need to know, so it’s a good place to start.

If you run into trouble with AppleJack, please look through the help forum first. If you can’t find your issue addressed there, look through the support requests, and if your issue isn’t addressed there, please file a support request of our own, and I’ll get back to you as soon as possible.

* Help Forum
* Support Requests

Uninstalling AppleJack

If you are running version 1.4.3 or later of AppleJack, you can uninstall by rebooting in single user mode and entering the command applejack uninstall. Alternatively, if you are logged in to your account, you can open a Terminal session and type sudo /var/root/Library/Scripts/ uninstall.

If you are running version 1.4.2 or earlier, you can download and run this script, which should remove all traces of an AppleJack installation. To uninstall:

1. Open a terminal window and type sudo bash (include the space at the end, but do not hit return yet!)
2. Drag the downloaded file to the terminal window. The line should now look similar to:
$ sudo bash /Users/username/Desktop/
3. Hit the return key. You will be prompted for your administrator password. Enter it, and the script will run.
4. If all goes well, your terminal should look similar to this:
$ sudo bash /Users/kit/Desktop/ Password: found AppleJack script. Removing… /private/var/root/Library/Scripts/ Searching for and removing any AppleJack man caches… Done. Restoring the root profile… Done. Searching for and removing AppleJack man pages… /usr/share/man/man8/applejack.8 done. AppleJack is uninstalled.

Installing AppleJack

Most people will probably want to use the installer that comes with the AppleJack distribution. If you would rather install AppleJack manually, take a look at a sample shell script that mimicks what the installer is doing.

What exactly is the installer doing? Well, it goes something like this:

1. It checks to see if the root user’s “.profile” exists, and if it does, removes any old references to AppleJack from it.
2. Then it creates an alias to the AppleJack script inside root’s .profile, so it can easily be called from single user mode (SUM). Also, the install routine creates a reminder about how to use AppleJack when you’re in SUM.
3. The script installs AppleJack in /private/var/root/Library/Scripts, creating the Library and Scripts folder along the way, if they don’t already exist.
4. The script installs the applejack man page into /usr/share/man/man8 (so you can get help on how to use AppleJack right from the command line by typing ‘man applejack’).
5. Then the script ensures that the AppleJack script and man page have the correct ownership and permissions, to keep others from tampering with it.
6. Finally, the script checks to see if there are old versions of the AppleJack man pages and removes them.


  1. John hatchell

    I maintain an older core 2 duo iMac for my niece, so it really only gets basic maintenance when I get down there to do it. Last time I was there, I installed Applejack on her computer in case she ran into any startup problems.

    Afterwards, I used Monolingual to clean up all the useless languages on the computer that had accumulated over the year.

    But I found when I tried to empty the trashcan, there was so much refuse in it that it would take hours to empty. So I ran Applejack on the off chance it could help.

    I was pleasantly surprised that Applejack cleaned up all the mess in the trashcan in one easy swoop. I love this product.

  2. stella


    I totally agree about Applejack.
    I use it on all my macs ( desktops and notebooks)
    However, I just ran into an issue in the past couple of months. I have a problem getting into single user mode.
    One desktop needs it. It just so happens
    I tried everything.

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