Each time a user visits a website using Microsoft
Internet Explorer,
files downloaded with each web page (including
html,
images,
Cascading Style Sheets and
JavaScript scripts) are saved to the
Temporary Internet Files folder, creating a
cache of the web page on the local computer's
hard disk, or other form of digital data storage. The next time the user visits the cached website, only changed content needs to be downloaded from the
Internet; the unchanged data is available in the cache.
Despite the name '
temporary', the cache of a website remains stored on the hard disk until the user manually clears the cache. This is often regarded as a privacy issue
[1] [2] [3], because anyone with access to the computer can view the cache. The contents of the folder are indexed using an
index.dat file, a form of database.
On
Windows XP, the cache is usually located at
%USERPROFILE%\Local Settings\Temporary Internet Files (where
%USERPROFILE% is an
environment variable pointing to the root directory of the logged-in user's
user profile). However, the cache may be
moved by changing a value in the registry. Occasionally an additional cache named "
Temporary Internet Files" may appear in
%USERPROFILE%\Local Settings\Temp\Temporary Internet Files. This location can only be deleted by manually accessing the folder and removing it. To date, no satisfactory explanation for the appearance of this directory has been located.
On
Windows Vista, the cache for
Internet Explorer 7 is usually located at
%LOCALAPPDATA%\Microsoft\Windows\Temporary Internet Files\Low\Content.IE5 where
%LOCALAPPDATA% is an environment variable pointing to
%USERPROFILE%\AppData\Local (note that the checkbox for 'Hide protected operating
system files' under 'Folder Options' must be unchecked and the 'Show
hidden files and folders' option enabled for the
files to be visible in
Windows Explorer). For all other
Trident-based applications, the cache is located at
%LOCALAPPDATA%\Microsoft\Windows\Temporary Internet Files. Like on Windows XP, the location of the cache can be changed by moving the folder location in
Internet Explorer or by changing a value in the registry.
The
Temporary Internet Files cache can be useful in certain situations. For example, if no
Internet connection is available, previously cached websites are still available offline. Certain online media
files (such as embedded Flash movies) are not easily accessed directly through
Internet Explorer, but are automatically saved into the cache after viewing them. Depending on the type of website and how often it is updated, the cached data may not reflect the online version of the website. The cache is also useful for police to collect
forensic evidence.
The cache can be cleared by using
Internet Options within the
Internet Explorer interface, but this method is subject to
deletion privacy issues. Many alternative tools exist to
erase the data instead.