Microsoft Office Document Filter
Indexing Service is no longer supported as of Windows XP and is unavailable for use as of Windows 8. Instead, use Windows Search for client side search and Microsoft Search Server Express for server side search.
This IFilter implementation (in offilt.dll) filters files for the documents in Microsoft Office, including the documents for Word, Excel, and PowerPoint. These include files with the extensions .doc, .mdb, .ppt, and .xlt.