What are Index.dat files?

Index.dat files are used by Internet Explorer and Windows to store history, Internet cache, cookies, UserData records 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 and Windows use them all the time.

Where are located Index.dat files?

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 Me, Windows 98, Windows NT or Windows 95 then index.dat files are in these locations:
C:\Windows\Cookies\index.dat
C:\Windows\History\index.dat
C:\Windows\History\MSHistXXXXXXXXXXXXXXXXXX\index.dat                  (XXXX are some digits)
C:\Windows\History\History.IE5\index.dat

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):
C:\Documents and Settings\<username>\Cookies\index.dat
C:\Documents and Settings\<username>\Local Settings\History\History.IE5\index.dat
C:\Documents and Settings\<username>\Local Settings\History\History.IE5
        \MSHistXXXXXXXXXXX\index.dat

What is in Index.dat files?

As already mentioned, index.dat files are binary files. Their content can be seen only with binary (hex) editor. We will examine an index.dat file from the Internet cache(Temporary Internet Files).
Actually the index.dat header is much larger but this is the most important part of it. The first thing is the version of the index.dat file (Client UrlCache MMF Ver 4.7) - this particular file is from Internet Explorer version 4 but the index.dat file format is very similar in Internet Explorer 5.x and 6.

How to erase or clean Index.dat files?

Erasing or cleaning of the index.dat files is not an easy task because they are opened by Internet Explorer and Windows all the time. If you are using Windows Me, Windows 98 or Windows 95 you can restart in DOS mode and then you can delete index.dat files one by one (look in the folders that are mentioned above). However if you are using Windows XP, Windows 2000 or Windows NT this won't work.
Mil Shield is a powerful privacy protection program that was designed specifically to clean and shred the index.dat files content. Unlike the other methods of dealing with index.dat file content, shredding is the best because it doesn't destroy the entire structure of the index.dat file which can cause Internet Explorer or Windows to crash but instead cleans and shreds only the privacy threatening URL, LEAK and REDR records.
Additional benefit is the ability to preserve the tracks from some chosen by you sites (selective cleaning), which makes your browsing more comfortable and safe (it is rather suspicious to always have empty history, cookies and cache - it is better to leave some tracks from "innocent" sites). Mil Shield also cleans all other tracks as cookies, history, cache, AutoComplete records, UserData records, history of recently used folders and documents and many other.

More information about the article: http://www.milincorporated.com/a_indexdat.html

Company profile:

Mil Incorporated was founded with an ambitious objective to be a trusted software partner for individuals and enterprises around the world. Mil Incorporated provides software security and privacy solutions that incorporate state of the art technology, security expertise, and substantial resources.

Web address: http://www.milincorporated.com/