lost username and password

• Mac OS X: Changing or resetting an account password:
http://support.apple.com/kb/ht1274

Usually, if you have the OS X install disc #1, and start the computer
from the Installer, with the C key held down, and then on the second
screen (do not actually install anything) you can see Installer appears
like a Finder window with menu bar across the top. An option in there
will allow you to reset the admin password. (A user name should
appear in the login screen. Is there nothing at all?)

Then, later, if you need to add a new account, within the running OS X
you can add an account in System Preferences> Accounts. That will
allow the new account, if so checked, to be an Admin or other account.
A new Admin account can be made to supersede an old Admin account.

{There also is a matter of forgotten or lost Keychain passwords.
That is another topic, should you find that to be a problem later.}

There are articles in Support (searchable) as well as online, to show/tell
how to go about more specific actions in OS X; by version.

• Mac OS X 10.4 Help: Changing your admin password:
http://docs.info.apple.com/article.html?path=mac/10.4/en/mh655.html

• Reset OS X Password, without an OS X CD or DVD:
http://gigaom.com/apple/reset-os-x-password-without-an-os-x-cd/

If the Admin account was deleted or otherwise lost, there are other ideas;
since I don't know exactly what the issue is, the solution(s) may vary.

*Lost Admin* privileges: may require command-line use of the root level
access into the computer (terminal) in order to act on the system there.
http://macosx.com/forums/howto-faqs/299801-howto-fix-user-lost-administrator-pri vileges.html

or: Lost admin user:
http://discussions.apple.com/thread.jspa?threadID=1323191

There is a way to look into the system in command line, to see a list of usernames.
Perhaps it was in the above link, that feature was mentioned... I've read so many.

A variety of possible solutions (or just similar worded situations) can be discovered
via using Google to search words: *Mac OS X: lost user name and password*
If you add the version of OS X you have, that may narrow down results a bit.

Anyway, hopefully just the use of the Install disc option to change password helps.
If there is no install disc, another way exists; though I don't remember it now.

Good luck & happy computing! 🙂

Does the computer start up* from an OS X install DVD or CD
version normally supporting the computer's hardware version?

(You did not specify if you have any tools or utilities; no info.)

*If so, and there's no login required when starting from an Install disc,
then you could be able to totally erase the computer & reinstall.

If the computer has a FileVault or a different kind of security set,
then even the booted installer disc won't be able to re-set that...

You would have to be more specific, in what you have, in order
to get into a closer match to what may work to access the Mac.

With the computer booted on startup into Single User or terminal,
there are ways to reset or change the password. If the FileVault
or other *firmware password* was set, you may have a different
set of problems. Physical access to a machine, where one can
open the unit and remove one RAM chip, can sometimes allow
someone not otherwise authorized, to gain access into software.

However, the above may be out of cue; I'm a bit rusty on this topic.

You were given this computer, and the original owner has no clues?
Normally, that'd be a bit suspect in and of itself. Proof of ownership?

What do you know about the computer? Model, year, OS X, specs?

• Encrypting with Mac OS X FileVault: (set-up & how it usually works)
http://main.uab.edu/Sites/it/faqs/55621/

• About FileVault: (per Mac OS X 10.4 Help)
http://docs.info.apple.com/article.html?path=Mac/10.4/en/mh1877.html

If the Master Password was set, then you'd need to have it & enter it
to be able to change the secondary password; once you're logged in.
There may be a few work arounds, when that is lost or forgotten, etc.
However, from what I've read, there is no workaround; if it is lost.

• Unlock a Mac stuck at 'Master Password' login screen
http://hints.macworld.com/article.php?story=20071129115342497

*What kind* of login window do you see? There is more than one kind.

If the screen you see is similar to what the above link describes, there
is a chance you could try their instructions; or a variant, to access it.

Or, try and boot from the Installer disc #1, and if you can get past a
login screen on startup (not set by FileVault or Master Password)
you could use that Installer and do a basic re-set of Admin password.

And, with a normal Admin account, use the new/reset PW to log-in.
Once in, you could change other settings to not see login on startup:
Unless the system has a FileVault, encrypted system, or Master Password.

(I can set my computer to require a password on wake up, also, set to
require password on start up, and other options. Some users have a
computer set up to not use the Admin account on a daily basis; so as
to make the computer itself more secure, they use a standard account.)

If the security was set in firmware, then the rules for simply setting up
a new password won't work. There had been mention of another way
to work around this problem, in the legitimate sense, to gain access.

And if security is only on the contents of the computer's hard disk drive,
you should be able to boot the computer from an OS X install DVD that
is compatible with the hardware model of the computer; if it passes this
test & you can start from an installer disc, see if you can erase the HDD.

If you have nothing on there and can't access it via lost password, there's
nothing there to lose. However, if the firmware password was set, that
would be in the logic board of the Mac; even a replacement hard drive
is not likely to allow access, if that was the case.

• How To Create A New Administrator Account (single user? it may work)
http://www.hackmac.org/hacks/how-to-create-a-new-administrator-account/

Anyway, at this hour, I'd have to know more about what you have; to
include any bootable OS X install DVD or CD, and more about the Mac.
And I could use sleep more than I could justify further speculation, now.

Maybe some other Discussions reader can help...
Good luck & happy computing! 🙂

Here is the easy way round unless you have the install discs which give an option to reset your password.

Do exactly this :-

Boot into single user mode with Apple(command) and “S” (hold down both together on restart)

Then enter this exactly, mind to get the spaces and the . in the right place.

/sbin/fsck -y [Enter]
/sbin/mount -uaw [Enter]
rm /var/db/.applesetupdone [Enter]
reboot [Enter]

This allows you to not only "own" the machine (register in your name) but also reset other passwords of other user accounts - please be respectful of your friends privacy tho !!

And for any one else - a note on security - a good reason to use file vault/encryption - BECAUSE IF someone were to aquire your computor sale or otherwise, and you didn't securly erase or remove your HD beforehand - your life is theirs!!

I buy, fix and sell Macs as a hobby, is how I know.