Car1son's Emergency OS X Re-initialization instructions

How to Reset OSX without the Installation CD (Re-run "Welcome to Macintosh")

This procedure will cause your OS X Macintosh to repeat the initial setup procedure. You can use this to get it to create a new administrative account when all hope fails.

In my test, my existing accounts, data, and network locations were not affected by this. (Don't specify a "Name" that already has an account on the computer, though! Make a new name! You may find the "Automatic" location of Network configs will be changed to reflect what you tell the initial setup application.) However, a current backup should be available in case things go wrong.

Boot to Single User mode (press power and hold command-S down until a bunch of white text will cascade down a black screen. (It's all Geek to me, too.) Eventually it stops at a # prompt. This is the Unix root.

Note: In the following, type the text shown in white after the "#" prompt. (The exact text in your prompt may vary with your exact OS X version.) Everything you type should be exact, including any spaces (you must put them where shown, and no place else.) This is critical! This isn't a Mac interface anymore. Unix is unforgiving, and it won't as you to confirm before trashing everything.

If using OS 10.1 or 10.2 you'll see a message suggesting running fsck, and that's a good idea. Type "/sbin/fsck -y":

2.05# /sbin/fsck -y

There must be a space between "/sbin/fsck" and "-y".
Then press RETURN.
That will take awhile, until you get another # prompt.
Then mount the root file system. Type "/sbin/mount -uw /":

2.05# /sbin/mount -uw /

There must be a space both before and after the "-uw".
Then press RETURN.
Now, remove the AppleSetupFile. This is a "magic file" - when OS X next boots, if it doesn't see that file, it will automatically run the initial setup utility. Type:

2.05# rm /private/var/db/.AppleSetupDone

There must be a space after the "rm" and no place else.
Then press RETURN.
Lastly, finish the boot. Type "exit":

2.05# exit

The Mac willre-run the setup program. You'll need to re-enter your name, short name, address, password and so on, and it will create a new administrator account with that name. Don't use the same name as any you used before - that alredy exists, and it will just confused things. You do not need confusion if it's come to this.

When you've answered all the questions, the Mac will log in the new account. You can use this account to recover data from the /Users folder of the old, damaged user account.

You can use the System Preferences Accounts pane to uncheck "Log this account in automatically" to try to log in as one of your old accounts.

If something above seems missing, confusing or down-right wrong, you can eMail me as car1son at my .Mac account. (Please be specific at what point things went wrong and how they went wrong.)

Good luck!