NOTE: See The Multilingual User Interface Pack (MUI) for Windows Desktop Search 2.6.6 is available.

Microsoft Knowledge Base Article 926356 contains the following INTRODUCTION:

This article discusses the availability of Windows Desktop Search (WDS) version 2.6.6. Additionally, this article describes the minimum system requirements to install Windows Desktop Search 2.6.6.

Windows Desktop Search 2.6.6 was released on November 28, 2006. This release includes improvements in stability and in performance to help enhance the search functionality. Windows Desktop Search 2.6.6 includes the following improvements:

An update to exclude or to remove applicable content after you apply the Prevent Indexing of Uncached Exchange Folders Group Policy.
An update to let the index location be changed to a Universal Naming Convention (UNC) path.
An update to fix the preview of .xml files.
An update to make sure that the index is updated successfully when you add, move, or remove e-mail messages that are related to third-party protocol handlers
An update to Group Policy to let you hide the Web search button.
An update to Group Policy to allow for bandwidth throttling of the Indexer.
Performance improvements for the initial indexing operation.
Product updates that are based on Windows error reports that we have received from customers.

Windows Desktop Search 2.6.6 is available as a free download from the Microsoft Download Center.

Note You can install Windows Desktop Search 2.6.6 as a new installation, or you can upgrade to Windows Desktop Search 2.6.6 from an earlier version of Windows Desktop Search 02.06.xxxx. If you upgrade to Windows Desktop Search 02.06.6000 from build 02.06.5000.5401, you do not have to rebuild the Windows Desktop Search index.