Fixed: Windows XP Logon Logoff Loop
One of my clients caught a virus on her computer this last week. In an attempt to correct the problem, she installed Norton Antivirus 2010 before doing a full system scan using the boot disk. The first time she rebooted the computer, she got into a logon logoff loop; after entering her login information and submitting it, Windows XP would automatically logoff the account. It was at this point she contacted me and I came to help her solve the problem. [See the bottom of this post for the solution]
I was stumped rather quickly after many internet searches. I could tell the solution would not be easy. The logon logoff loop persisted in all versions of safe mode; I was unable to access a command prompt. I ran the bootable Norton CD and cleaned any remaining viruses off the machine; that didn’t solve the problem. My attempts to rename or copy files from another working machine, using a Windows Repair Console, did not solve the problem either.
Before telling my client I could not fix the problem, I called Norton to see if they could help me. Norton’s support was unacceptable, they could not help me. I documented Norton’s inadequate support in a separate post.
I brought the computer to Best Buy, where my client originally purchased the Norton product. I talked with the Geek Squad agent for a while, and we came to the same conclusion, a Windows Reinstall was most likely necessary. I told my client I could do this at a fraction of the cost Best Buy would charge.
I attempted one last time to save the instillation of Windows, and returned to the internet once more. I quickly realized I had managed to miss one of the possible solutions; fixing the registry. I originally did not try this because I was unable to access Regedit. This time, however, I brought some blank CDs and a copy of Windows XP Professional SP2 so that I could create a BartPE disk. Using that disk I was able to open the local machine’s software registry hive and solve the problem. My client’s computer booted successfully, and everything was as good as it was pre virus infection.
I learned two lessons with this service call:
- Run a full system scan prior to an Antivirus instillation; the scan provided on the bootable CD.
- The Bootable Norton CD will download new virus definitions automatically if the machine is connected to a LAN.
- Installing Norton on an infected machine could possibly cause damage.
- Come to all clients with all the tools at your disposal. Even the tools you don’t think you will need.
A Windows XP Professional machine was infected with several viruses. Norton Antivirus 2010 was installed prior to a full system scan.
After rebooting, the system enters a logon logoff (or login logoff) loop; unable to get to the desktop. Safe mode will not work.
- Boot from BartPE disk (Download and creation instructions for BartPE)
- Open Regedit
- Select the HKEY_USERS hive
- Click File and choose Load Hive
- Open the SOFTWARE registry hive, likely located in:
C:\Windows\System32\Config\SOFTWARE (Note: No filename extension)
- Give the Hive a name: MyLocalHive
- Navigate to:
- Validate the value for the Userinit string equals:
C:\Windows\System32\Userinit.exe, (Note: comma should be there)
- The preceding string and value may be missing and must be added
- Close Regedit and reboot the machine
Solution Credit: MVPS.org