How can I include a specific file type in a file system search under Windows XP?

A. To avoid misleading results, the Windows XP Index service filters out certain file types (i.e., doesn't consider those file types) when you perform a text search. As a result, the Index service might not return the expected search result, even though you might know that the phrase you're searching for exists. To manually add specific file types to be included in a file system search, perform the following steps:

1. Start a registry editor (e.g., regedit.exe).
2. Navigate to the HKEY_CLASSES_ROOT\.cxx\PersistentHandler registry subkey.
3. Look for a key that matches the extension for the file type you want to include in your search (e.g., .sgl). If the key doesn't exist, create a new key, including the period in the key name (e.g., .sgl).
4. Under the file extension, create a new key called PersistentHandler (go to the Edit menu, then select New, Key).
Navigate to the PersistentHandler registry subkey, then double-click the (Default) value.
5. Set the value to \{5e941d80-bf96-11cd-b579-08002b30bfeb\}, then click OK.
6. Restart your computer for the change to take effect.

To check which extensions XP includes in a search, you can use regedit to search for the \{5e941d80-bf96-11cd-b579-08002b30bfeb\} value. On my machine, file types that have the PersistentHandler value include .asm, .bat, and .c.

Likewise, if you want to exclude a file type from future searches, simply remove its PersistentHandler value and restart the machine. The XP Application Compatibility Update dated October 25, 2001, added many file-extension types to be included in searches. If you don't have this update, you should install it first. You can download the update from Microsoft's Web site.