Index.dat file – What is Index.dat file?

Index.dat are files hidden on your computer that contain all of the Web sites that you have ever visited.  Every URL, and every Web page is listed there.  Not only that but all of the email that has been sent or received through Outlook or Outlook Express is also being logged.

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.

According to Microsoft, these files are used to cache visited Web sites to help speed up the loading of Web pages in Internet Explorer.  Obviously this cannot be the case because when you clear the Temporary Internet Files the “index.dat” files remain behind and continue to grow.  If you delete or clear the Temporary Internet Files, there is absolutely no need to index the URL cache because those files no longer exist.

On a Windows 9x computer these files are located in the following locations:
\WINDOWS\Cookies\index.dat
\WINDOWS\History\index.dat
\WINDOWS\Temporary Internet Files\index.dat
\WINDOWS\Cookies\index.dat
\WINDOWS\History\index.dat
\WINDOWS\Temporary Internet Files\index.dat

In Windows 2000 and Windows XP there are several “index.dat” files in these locations:

\Documents and Settings\<Username>\Cookies\index.dat

\Documents and Settings\<Username>\Local Settings\History\History.IE5\index.dat

\Documents and Settings\<Username>\Local Settings\History\History.IE5\MSHist012001123120020101\index.dat
\Documents and Settings\<Username>\Local
Settings\History\History.IE5\MSHist012002010720020114\index.dat

\Documents and Settings\<Username>\Local Internet Files\Content.IE5\index.dat