Windows Search and XDP files

By default the Windows Search will only pick up the file properties of XDP files.  But since XDP files are really just XML files we can set the search filter handler to the XML Filter and then our search will look in the element and attribute values of the XDP file.

To do this we need to edit the Registry.  If we look at the registry key for the .xml file type (which has a key of HKEY_CLASSES_ROOT\.xml) we see

To make Windows Search treat XDP files like XML all we need to do copy the PersistentHandler key with a default value of the GUID for the XML Filter which is {7E9D8D44-6926-426F-AA2B-217A819A5CCE} to the XDP class key HKEY_CLASSES_ROOT\.xdp.

Once we have done that, if you go to Index Options, select Advanced ... File Types and scroll down to XDP you will see the XML Filter is being used.

Make sure you have the "Index Properties and File Contents" selected, then go back to Index Settings tab and click the Rebuild button ... wait several hours and your searches will now include the contents of the XDP files.