After Windows starts, the registry may be missing a subset
of keys under a subkey such as HKLM\Software\Classes or
HKLM\Software\Classes\CLSID. Because many of these keys are required for Windows to work correctly, Explorer.exe may not start after you log on, Windows Management Instrumentation (WMI) may not work
correctly, or a program may not work. If you view the registry closely (by comparing the registry with that from a working computer, or through troubleshooting), you may find many missing keys.
The registry resiliency code in Windows XP Service Pack 1 (SP1) removes corrupted
registry keys when Windows starts, but may inadvertently delete a subset of
Service pack information
To resolve this problem, obtain the latest service pack for Microsoft Windows XP. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
How to obtain the latest Windows XP service pack
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. The English version of
this fix has the file attributes (or later) 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 tool in Control Panel.
Date Time Version Size File name
18-Feb-2003 14:01 5.1.2600.1170 1,892,352 Ntkrnlmp.exe
18-Feb-2003 14:02 5.1.2600.1170 1,948,288 Ntkrnlpa.exe
18-Feb-2003 14:02 5.1.2600.1170 1,921,024 Ntkrpamp.exe
18-Feb-2003 14:01 5.1.2600.1170 1,924,480 Ntoskrnl.exe
To prevent this problem from occurring, install the hotfix that is described in this article. If the problem has already occurred, restore the
missing registry keys from a backup.
has confirmed that this is a problem in the Microsoft products that are listed
at the beginning of this article.
This problem was first corrected in Microsoft Windows XP Service Pack 2.