Windows Explorer cannot find files

http://support.microsoft.com/default.aspx?scid=kb;en-us;309173


set the FilterFilesWithUnknownExtensions DWORD value to 1 in the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ContentIndex

Remember also to enable the "find hidden files" advanced option.

This is one of those jaw-dropping things ... why on earth would you NOT want to find files with unregistered extension...