This post discuss the ways to rebuilding the index, adding locations, add a new file type in to Windows Deskto Search. If you are not familiar with this option, in the Indexing Options applet in Control Panel, under the Advanced Options, there is a tab that lists the different file types and how they are indexed (see pic). In this specific instance, the question revolved around whether or not they could create a custom .ADM to modify these options, and if so, which registry key(s) did they need to modify to roll out the changes.  Now, on the surface, this probably seems like a fairly straightforward question.  However – the fact is that this list is auto-generated, partially by reading the different file type registrations and their associated iFilters from HKEY_CURRENT_ROOT.  In other words – the Indexer simply picks up the information that is used by the entire operating system to determine how different file types are handled.  By default, all file basic properties are indexed whether or not the file is registered in HKEY_CURRENT_ROOT.

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Additional Resources:

• MSDN: Windows Search Development Guide
• MSDN: Developing Property Handlers for Windows Search
• MSDN: IFilter