Index.dat are files hidden on your computer that contain all of the Web sites that you have ever visited. Every URL, cookies and browsing history is listed there. The file names and locations depend on what version of Internet Explorer you have. If you are running IE version 4.0 or above, the file name is "index.dat". Microsoft has not supplied an adequate explanation as to what these files are for or why they have been hidden so well.

index.dat Viewer reads the index.dat files directly. This makes sure that what you see displayed by the program are the exact contents of the index.dat files.