You can give this a try if you want. Enable Windows Search if is it not running already and visit some of your favorite websites. Now run CCleaner or another temporary file cleaner that deletes the history file of Internet Explorer, the web browser cache and the index.dat file.

Re-open Internet Explorer and enter letters of web addresses or titles that you visited previously in the search bar. You should see History suggestions in the suggestions bar, provided that you have not changed the settings in Internet Explorer or indexing options of Windows Search.

There are actually a few options available to block this from happening in the future. Probably the easiest option is right there available in Internet Explorer.

Click on Tools (or the Tools icon in Internet Explorer 9) and select Internet Options from the menu.

Switch to the content tab there and locate the AutoComplete section in the menu.

It reads “AutoComplete stores previous entries on webpages and suggests matches for your”. Click the Settings button next to the description.

Check to see if “Use Windows Search for better results” is enabled. If it is remove the checkmark from the checkbox. This disables the feature so that no history information of Internet Explorer are stored by Windows Search. Click the Delete AutoComplete history button on your way out if you like to remove all existing entries.

Disabling the option is the easiest way to break the connection between Internet Explorer and Windows Search. Users who do not use Windows Search at all can disable the search service instead which disables the feature automatically as a consequence.

A few software programs are available to view and delete the contents of index.dat files. We have mentioned some of them earlier here at Ghacks like the index.dat viewer or the index.dat suite. Another tool for the purpose is the index.dat analyzer which can display and clean the contents of index.dat files as well.

If you want to prevent that Windows is writing data to those files in future sessions you need to set the file attribute to read-only. Another possibility would be to run CCleaner regularly (this can be automated) to clean the index.dat files.

An index.dat viewer is a tool that can display the information stored in those database files. Index.dat Scanner is such a viewer that can scan all index.dat files on the computer that it can located or a specific one that the user selects from the system. The scan takes some time but results are displayed as they are found.

The software program will list all of its findings in a list that can be exported as a text document. It did find more than 4000 entries on the test computer although Internet Explorer itself was rarely used on it. The information listed in the index.dat databases list recently opened files, urls that the user visited in the past and cookies that have been stored during browsing sessions.

The index.dat files are by default hidden locked system files that cannot be deleted in Windows directly. Several tools like CCleaner exist that can clear the contents of index.dat files on a Windows system directly which is probably the easiest way to clean those files. Index.dat Scanner can be used to check if all traces have been deleted in the files.

It is obviously important to run the cleanup regularly because the files get populate whenever a file gets opened or Internet Explorer opens a website.

The major problem that I have with index.dat files is that they raise privacy concerns. They cannot be opened in a text editor but are easily viewable with the right viewer. One of these tools that you can use is the Index.dat Suite which is probably the most advanced software that is freely available.

Before I start I would like to mention that Internet Explorer uses three different index.dat files which contain the history, cookies and cache. Other applications make use of index.dat files as well, Microsoft Office for instance uses it to save the recent documents.

When you first start the Index.dat Suite you are asked to perform a scan of your system for index.dat files. You can speed up the process if you filter the scan by drive. All my applications that produce index.dat files are located on drive C which meant that I only scanned that drive.

The list will be huge. Each user account has index.dat files in the home directory. Most of those are default files if the account is not in use actively with a size of 16,32 or 128 Kilobyte. The interesting files are those of active accounts because they contain data that is viewable, if Internet Explorer is used that is.

I discovered a 4 Megabyte index.dat file on my system dating back to Internet Explorer 5 that contained many urls that I visited at that time.

Once the scan finished you can right-click any index.dat file in the list and use the internal viewer to see its contents. The contents depend on the type of index.dat file that you open, you either see a history file, Temporary Internet Cache or cookies.

The suite does not only provide ways to view the contents of the files. It is furthermore possible to clean them effectively. They are however created anew when Internet Explorer is started again.

The file index.dat which exists many times on windows xp accounts, to be precise many times for every user, stores visited urls and cookies for instance even though you deleted that information before. Microsoft surely has a good explanation for this, right ? They say it is to speed up Internet Explorer but this sounds somewhat fishy, why would you need for instance the cookies if you have deleted them ?

To find index.dat on your computer you need to do the following (Win xo only). Open any folder, click on tools, folder options. Select view from the tab and uncheck “hide protected operating system files” and make sure “Show hidden files and folders is enabled”. Now search for index.dat and windows will come up with some search results.

It does help to view the file in an normal editor, it won’t show anything. What you need to do to see the list of urls or cookies is to download the sweet little tool Pasco created by Keith Jones. It is a freeware command line utility. Unpack it, copy any of the index.dat files into the bin dir of pasco and fire up the command line mode of windows xp. (Hit Windows key + R, enter cmd and hit enter)

Change to the pasco dir and enter the following command:

pasco index.dat > urls.txt

Pasco creates a text file with all urls that are saved in the index.dat file. You can then view the with every text editor available. The same works with the index.dat that holds the cookies of course.

Ever wanted to know what your kids, husband, wife, friends, co-workers do when they are alone ? Use the index.dat file to find out.

How to remove the index.dat file:

The index.dat file is protected in windows and you will have a hard time deleting it from within.

These data files are used by Internet Explorer and Windows Explorer. You cannot delete a file that is in use by a running program. If you feel you need to delete the file, you will have to shutdown all instances of Explorer and IE. This includes applications that may host the Webbrowser control: Outlook, Messenger, IE, Product Studio, Visual Studio, Help, Windows Media Player, etc. Your best bet is just close everything. When you are left with a desktop and a start menu, you will still need to shutdown Explorer. To cleanly shutdown Explorer: Start->Shutdown->CTRL+ALT+SHIFT+Click ‘Cancel’ (for more info, see this post). You can use Task Manager (CTRL+SHIFT+ESC, File->Run…) at this point to open a command window. You should be able to go delete the index.dat. I have only tried this on XPSP2, but it should work anywhere.

thanks to Jeff for this information

Another way would be to boot either into safemode or dos to kill the file.

The new Internet Explorer 7 apparently fixes this issue.