Index.dat files are used by Internet Explorer to store history, Internet cache, cookies and other information about what you have done in Internet or in your PC. Although some of their functions are useful, they are dangerous privacy threat - any person with even little knowledge about index.dat files locations and structure can see history of almost all of your computer activities. Index.dat files are not the only privacy threat but they are the most obscure and dangerous one because they are hard to find and even harder to delete. In fact, in most cases it is impossible to delete Index.dat files manually because Internet Explorer use them all the time.

There are three kinds of index.dat files, all of them having the same structure but storing different kinds of information.

1. Temporary internet files index file. This one is storing almost all the addresses of the html and pictures you opened in your browser. Cleaning the temporary internet files won't help, it will only remove the files, but it will keep the records in this file.
2. Cookies index file. This file contains a list of cookies placed on your computer by sites you visited recently. Cleaning the cookies usually removes most of the records from this file, but there may be leftovers that were not deleted (usually less than 10).
3. History index files. These files contain all the URLs you ever opened on your machine. There can be more than one file; usually it creates one of every week.

The location of index.dat files depends on the version of Windows and whether or not you are using user profiles. Regardless of Windows version in many cases you can't see or find index.dat file using Windows Explorer. There is a little file called desktop.ini in each directory where index.dat file is located. This desktop.ini file forces Windows Explorer to hide index.dat files and to show the contents of Internet cache or history instead. However you can use some other file utility and binary (hex) editor to find the files and read their content. If you have Windows Vita then index.dat files are in these locations (note that on your PC they can be on other drive instead of drive C):

Note, that you will have to change the settings of Windows Explorer to show all kinds of files (including the protected system files) in order to access these folders.

If you have Windows XP or Windows 2000 then index.dat files are in these locations (note that on your PC they can be on other drive instead of drive C):

If you have only one user account on Windows XP or Windows 2000 then replace <username> with Administrator to get the paths of all index.dat files.

If you have Windows Me, Windows 98, Windows NT or Windows 95 then index.dat files are in these locations:

Index.dat files are always being used by windows system, you can not delete them manually, and even you clear Temporary Internet Files on Internet Option of Internet Explorer, it will not delete them.

Using Free Window Sweeper to delete index.dat files is very easy, just select the Index.dat on the Cleaner Settings list.

Free Window Sweeper can overwrite all index.dat files with blank characters so that no one can see useful information from these files.

Why are those deleted index.dat files still there?

    Index.dat files are protected system files. Therefore you can not delete index.dat files as long as Windows is running. That's why Free Window Sweeper needs to restart your PC in order to delete index.dat files. Also index.dat files will be created automatically by Windows even they are deleted. So you will see those index.dat files stiill there. But you can see the content from "Index.dat Viewer" before clearing them. Then you can clear them and see again from "Index.dat Viewer". You will find the history in those index.dat files had been cleared. But you also can see the files still exist and the file size will be smaller.

If you like Free Window Sweeper, please feel free to donate, any donations large or small are greatly appreciated. Your donation, therefore, means a lot to me and will help me continue writing programs and maintaining the website. I search the internet and collect many system cleaner software. I hope you can like them.

Thanks for your help.