[nder]

A friend upgraded his PowerMac G4 from OS X 10.4.2 to 10.4.6 and it has resulted in some sort of corruption with the Admin user account.

Whenever he logs in he says: "it starts the login process (accepts or disallows password depending on if you type it correctly) and dies just as the menubar, desktop and dock are to appear".

He has removed all settings and files from his home directory, but still not going through. He has removed and recreated his account also, and it still wont work. However, the new account gets the same UID, so something thats associated with the account name/uid is hanging around.

His Admin user account is the only account affected by this problem.

Any ideas?

[Nivag]

have you tried Safe Booting into the Admin account?

To start up into Safe Mode (to "Safe Boot"), do this:

Be sure the computer is shut down.
Press the power button.
Immediately after you hear the startup tone, press and hold the Shift key.
Tip: The Shift key should be held as soon as possible after the startup tone but not before.
Release the Shift key when you see the gray Apple and progress indicator (looks like a spinning gear).
During the startup in Mac OS X 10.2 through 10.3.9, you will see "Safe Boot" on the Mac OS X startup screen.

During the startup in Mac OS X 10.4 or later, you will see "Safe Boot" on the login window, which appears even if you normally log in automatically.

To leave Safe Mode in any version of Mac OS X, restart the computer normally, without holding any keys during startup.

http://docs.info.apple.com/article.html?artnum=107393

That can sometimes solve login problems or has yr friend run repair permissions?

If it doesn't just create a new Admin account and delete the old one. but making sure you've backed up anything in the Admin user account.

[nder]

He has tried safe booting. Didn't work.

The thing is that he wants back the old username, but everytime he creates the account with the old username it gets the same UID and doesnt work.