Windows XP locks up - "SHCreateThreadRef could not be created" error

If you receive an error message: "Explorer.EXE - Entry Point Not Found - The procedure entry point SHCreateThreadRef could not be located in the dynamic link library SHLWAPI.dll", this information will help resolve the issue.

This appears to have been caused by the following sequence of events:

1) You installed Windows XP Service Pack 2

2) The installation of Service Pack 2 failed due to a computer crash during the installation which caused the automatic Service Pack Recovery process. On next boot, you would have received an error message telling you that the install failed, and you need to go to the control panel and uninstall SP2 and then try re-installing it. This message may have been dismissed accidentally or by another individual using your computer. In any event, the Service Pack recovery process was not completed by uninstalling the service pack from the add/remove programs control panel, and the system is in a partially installed state which is not stable.

3) You then installed the latest security update for Windows XP, MS04-038, KB834707. Because your system is still partially SP2, the SP2 version of this fix was downloaded and installed by Windows Update or Automatic Updates. However, the operating system files on the system are the original versions due to the SP Recovery process. This results in mismatched files causing this error.

To recover the system, carefully do the following steps:

1.. Boot normally and attempt to log in to your desktop. At this point you should get the error message listed above.

2.. Press Control+Alt+Delete at the same time to start the Task Manager. You may get additional error messages but Task Manager will eventually start.

3.. On the menu bar, select File and then New Task (run).

4.. Type in "control appwiz.cpl" into the new task box and hit OK. You may get additional errors that can be ignored.

5.. The Add/Remove Control Panel should now be running. You can close task manager.

6.. Near the bottom of the list, find the entry titled "Windows XP Hotfix - KB834707".

7.. Click on it and click the "Remove" button. It will take some time to complete, up to 15 minutes - it can also look like it's locked up, it's not. Once the "Finish" button is visible, click on it and reboot your system. If you get messages about additional software or hotfixes installed, you can safely ignore them.

Do NOT stop now! Your system is still in the "failed SP2 install" state. You MUST complete the SP2 uninstall, and then re-install SP2.

8.. Start the system and log in.

9.. Click on Start and then Control Panel.

10.. Click on the Add/Remove programs item.

11.. Near the bottom of the list, find the entry titled "Windows XP Service Pack 2" entry.

12.. Click on it and remove Service Pack 2, this can also take 10 - 15 minutes or more.. You may get a warning about software you have installed after SP2. Make a note of it as you may need to reinstall some of if after the uninstall operation.

13.. After Service Pack 2 has been successfully removed, you may notice your mouse isn't working anymore (especially optical mice). You will need to restart the computer manually by either pressing the windows key or Ctrl+Esc (if your keyboard doesn't have a windows key) to open the start menu. Then use your arrow keys to select "shutdown" and then "reboot".

14. Once your computer restarts again, you will notice your screen resolution is different and the icons are larger. Your mouse may still not be working. This is normal. Just let Windows run for about 10 minutes. It will start detecting all the hardware and re-installing drivers for everything. This includes your video and mouse. When it is finished, your mouse should be working again. When you don't see Windows detecting any more hardware, restart the computer. It should now boot normally into a pre-sp2 state. You can then run the service pack agian to update to SP2.

15. you should visit http://www.microsoft.com/sp2install, for instructions on installing Service Pack 2. You can get SP2 from http://windowsupdate.microsoft.com.

16.. After Service Pack 2 has been successfully re-installed, you should re-visit Windows Update to get the proper version of the latest critical security updates.

FAQ:

Q: I don't believe I am in the "partially installed SP2 state." Is there any way to check that?

A: After step 7, your system should be able to log in. There are several ways to check.

1. Open the file c:\windows\svcpack.log, and scroll to the very bottom of the file. About 10 lines from the end, you should see:

0.xxx: Executing script \SystemRoot\sprecovr.txt

0.xxx: In cleanup mode. System will not be rebooted.

If you have these lines in svcpack.log, and you did not uninstall Service Pack 2 in Add/Remove programs, you definitely have a machine in this partially installed state.

2. Click on Start menu, then Run, and type "winver". If the version is "Version 5.1 (Build 2600.xpsp_sp2_rtm.040803-2158: Service Pack 2" then you have the correct SP2 install. If, however, it has a number that begins with a 01, 02 or 03 or any number less than 040804 after the xpsp2, such as Build 2600.xpsp2.030422-1633 : Service Pack 2" then you definitely have a machine in the partially installed state.

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