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When you restart a computer that is running Microsoft Windows XP Professional, you may randomly receive the following error message:
Note You may experience this problem more frequently if Group Policy is applied immediately before the computer is restarted.
This problem occurs if the Winlogon.exe program crashes during the Windows startup process. In this situation, a "Stop 0xC000021A" error message occurs.
This problem occurs if the Wbemprox.dll library is unloaded prematurely. In this situation, the Component Object Model (COM) proceeds with the unload operation because the following conditions are true:
COM does not detect that a particular thread is still using COM.
The particular thread has the Wbemprox.dll library on its call stack.
This problem occurs because the Userenv.dll library does not call the CoInitialize function on the particular thread.
A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.
If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.
Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:
Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.
Because of file dependencies, you must be running Windows XP Service Pack 2 (SP2) to apply this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
322389 How to obtain the latest Windows XP service pack
You must restart the computer after you apply this hotfix.
Hotfix replacement information
This hotfix does not replace any other hotfixes.
The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates