The Temporary Internet Files (TIF) system is used to cache HTML, graphics and cookies saved when viewing a Web page and the index.dat file for the TIF.
The index.dat file is held open by Windows for fast access but because its open then it can't be deleted.
If you set CCleaner to delete the index.dat file then it is deleted as Windows boots up and a fresh copy is created by Windows.
This is also how Index.dat Suite works but Index.dat Suite has more features:
* View and delete index.dat files
* View and delete Temporary Internet Files (TIF)
* View and delete Cookies
* View and delete History
* View and delete Temp files
* View and delete Recent Documents
* Delete Typed URL's
* Delete Prefetch folder contents
* Auto-generation of batch file to assist in deleting the index.dat files in DOS.
* Optional add to RunOnce registry key
* Optional deletion of swap file (9x users only)
* Optional defrag after file deletion
* Full application logging
http://support.it-mate.co.uk/?mode=Product...=index.datsuite
The truth about the index.dat files: What, why and where?
by Steven Burn
http://mysteryfcm.co.uk/?mode=Articles&date=01-11-2005