Index.dat
Encyclopedia
In the Microsoft Windows
operating system
, index.dat is a database file used by the Internet Explorer
web browser
. It is used to improve performance.
, search queries and recently opened files. Its purpose is to enable quick access to data used by Internet Explorer. For example, every web address visited is stored in the index.dat file, allowing Internet Explorer to quickly find Autocomplete matches as the user types a web address. The index.dat file is user-specific and is open as long a user is logged on in Windows. Separate index.dat files exist for the Internet Explorer history, cache, and cookies.
The index.dat file is never resized or deleted. A large index.dat file can impair performance.
groups contend that the use of index.dat files in the Windows operating system is an invasion of users' privacy. The information contained in an index.dat file can be considered private to the user. One of the groups' main complaints is that the index.dat files cannot easily be deleted. This is because windows prevents open or "locked" files from being deleted.
It has been contended that the means provided by the Windows operating system for removing information from the index.dat files give a false sense of security. Although the internet cache folder can be cleared, its use cannot be disabled. Also, removing individual entries from an index.dat file (for example, by using Windows Explorer
) only prevents those entries being used; it does not remove the files referenced until the next "cleanup". (Marking single entries as deleted rather than erasing them is a common database method of quickly removing items from use whilst also retaining those items should it be desirable to reverse the deletion.)
While some have claimed that the Windows Operating System deliberately hides index.dat files, others point to the fact that Windows Explorer offers users a detailed view of the content of the files when browsing containing folders, even allowing the removal of specific entries.
Various free programs (among them Red Button, CCleaner
, Index.dat Suite), can completely remove index.dat files until they are recreated by Windows, though CCleaner, and perhaps the others, does not delete the hidden index.dat file in the Temporary Internet Files folder, which contains a copy of the cookies that were in the Cookies folder. However, if Secure Deletion is enabled in CCleaner then this will effectively wipe the contents of this file although the size will continue to increase with use.
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
, index.dat is a database file used by the Internet Explorer
Internet Explorer
Windows Internet Explorer is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems, starting in 1995. It was first released as part of the add-on package Plus! for Windows 95 that year...
web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...
. It is used to improve performance.
Function
The index.dat file is a database file. It is a repository of information such as web URLsUniform Resource Locator
In computing, a uniform resource locator or universal resource locator is a specific character string that constitutes a reference to an Internet resource....
, search queries and recently opened files. Its purpose is to enable quick access to data used by Internet Explorer. For example, every web address visited is stored in the index.dat file, allowing Internet Explorer to quickly find Autocomplete matches as the user types a web address. The index.dat file is user-specific and is open as long a user is logged on in Windows. Separate index.dat files exist for the Internet Explorer history, cache, and cookies.
The index.dat file is never resized or deleted. A large index.dat file can impair performance.
- Note: The .dat extension is commonly used for data files (files that are not human-readable and do not hold a document-based binary file). It's possible to find files named 'index.dat' that are not used by Internet Explorer.
Controversy
Internet privacyInternet privacy
Internet privacy involves the right or mandate of personal privacy concerning the storing, repurposing, providing to third-parties, and displaying of information pertaining to oneself via the Internet. Privacy can entail both Personally Identifying Information or non-PII information such as a...
groups contend that the use of index.dat files in the Windows operating system is an invasion of users' privacy. The information contained in an index.dat file can be considered private to the user. One of the groups' main complaints is that the index.dat files cannot easily be deleted. This is because windows prevents open or "locked" files from being deleted.
It has been contended that the means provided by the Windows operating system for removing information from the index.dat files give a false sense of security. Although the internet cache folder can be cleared, its use cannot be disabled. Also, removing individual entries from an index.dat file (for example, by using Windows Explorer
Windows Explorer
This article is about the Windows file system browser. For the similarly named web browser, see Internet ExplorerWindows Explorer is a file manager application that is included with releases of the Microsoft Windows operating system from Windows 95 onwards. It provides a graphical user interface...
) only prevents those entries being used; it does not remove the files referenced until the next "cleanup". (Marking single entries as deleted rather than erasing them is a common database method of quickly removing items from use whilst also retaining those items should it be desirable to reverse the deletion.)
While some have claimed that the Windows Operating System deliberately hides index.dat files, others point to the fact that Windows Explorer offers users a detailed view of the content of the files when browsing containing folders, even allowing the removal of specific entries.
Various free programs (among them Red Button, CCleaner
CCleaner
CCleaner , developed by Piriform is a Utility program used to clean potentially unwanted files and invalid Windows Registry entries from a computer...
, Index.dat Suite), can completely remove index.dat files until they are recreated by Windows, though CCleaner, and perhaps the others, does not delete the hidden index.dat file in the Temporary Internet Files folder, which contains a copy of the cookies that were in the Cookies folder. However, if Secure Deletion is enabled in CCleaner then this will effectively wipe the contents of this file although the size will continue to increase with use.
External links
- Windows Networking Team blog about Index.dat (followup Q&A)
- How to remove index.dat (Site has broken links)
- A Cleanup API for Windows - details on how to delete index.dat files
- Windows 'index.dat' Parser Free tool that can be run on Windows, Linux or Mac OS-X.