You cannot perform a search query after you upgrade to Windows SharePoint Services 3.0

You perform an in-place upgrade from Microsoft Windows SharePoint Services 2.0 to Microsoft Windows SharePoint Services 3.0. When you try to perform a search query, you receive the following error message:

This problem occurs when the Windows SharePoint Services 2.0 server application pool account is configured to use the NETWORK_SERVICE account.

How to obtain the hotfix

This issue is fixed in the Windows SharePoint Services 3.0 Hotfix Package that is dated April 12, 2007. For more information, click the following article number to view the article in the Microsoft Knowledge Base: Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To enable this hotfix, follow these steps:

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry key:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\12.0\Search\Global\Gathering Manager
3. Double-click AllowNetworkService.
4. In the Edit DWORD Value dialog box, type 1 under Value data, and then click OK.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.