subject: fix: XP: instant logoff on logon posted: Sun, 16 May 2010 22:16:37 +0100
Problem:
You cannot login to a Windows XP machine. You see the login screen
and can enter a username and password (which must be correct),
however immediately followjng the "Logging on..." message, you see a
"Logging off..." message, and you are returned to the login screen.
This behaviour occurs no matter which account you login to, including
Administrator, and occurs in Safe mode as well as in Normal mode.
Cause:
Note: this problem may have multiple causes and solutions. The fix
presented here may not work in all circumstances.
This problem is caused by a missing/corrupted registry key, and/or
file. The file is:
1. c:\windows\system32\userinit.exe exists, and is identical to the
userinit.exe on the XP CD, or identical to the userinit.exe in the
ServicePackFiles directory (etc). A virus may try to replace this
file with itself. If replacing from old media, ensure to run SFC
(once you can login).
Note that as the computer cannot be logged into, this step must be
done with a boot CD - either XP's own Recovery Console, or a third-
party tool such as BartPE.
2. the registry key above is set as follows:
c:\windows\system32\userinit.exe,
The trailing comma is needed (apparently).
Note that as the computer cannot be logged into, this step must be
done with a boot CD. XP's own Recovery Console **does not** provide
the ability to edit the registry. Therefore, this step cannot be
done with the Recovery Console - it needs BartPE (or equivalent).
Notes:
1. BartPE is very cool, it's a bootable XP CD, it has a GUI, it
supports a mouse and networking, and it has loads of plugins. It's
here:
search: