What Is a Temporary Internet File? A temporary Internet file is a file that is located on your hard drive that a browser uses to store Web site data for every Web page or URL address that you visit. When the Web server sends the Web page files to the browser, they are stored in a file so that the next time you visit the same Web site the browser takes the data from the temporary Internet file. Loading the Web site in this way from a temporary Internet file is called caching. With this method, the page quickly displays in the browser instead of having to wait for response from the Web site's server all over again. Basically, the browser is opening the Web page from your hard drive instead of downloading the files from the Internet. Only the new content since your last visit would be downloaded on consecutive visits to a Web page. Not only is it faster to view the content from your temporary Internet files rather than from the Web server, but if your Internet connection is unavailable you can view the cached versions of recently visited Web pages while offline. Where Are They Stored On My Computer? On a Windows-based computer Temporary Internet Files is actually the name of the directory used by Internet Explorer to cache the pages you visit. Many different types of files are saved to the Temporary Internet Files folder when you visit a Web page, such as HTML, images, JavaScript, style sheets, video files, cookies and more. If you're using Firefox rather than Internet Explorer the term cache is used instead of Temporary Internet Files.

Thank you mohammed.samad, but I know all that and more. Problem is, I always meticulously clean up my cache immediately after having been browsing (even using CCleaner), and this always helped. I suspect there has been some policy change somewhere, making this cleaning less effective. I wonder what to do about that, for our rather detailed backup and cleanup system is getting a bit overwhelmed...

Normally the cache would be in AppData\Local\Mozilla\Firefox\Profiles\ and not in Roaming, see about:cache

• https://support.mozilla.org/kb/Clear+Recent+History

Thanks cor-el, but I know all that. Things is, *normally* is a term that doesn't apply in my case. The avalanche these last few weeks *does* happen in Roaming, and all my settings are such that the stuff should disappear - as indeed it happens to the similar stuff in the Local subfolder. But why is all that clutter (also) dumped in Roaming, and why isn't it cleared?

Are the files in the main profile folder (xxxxxxxx.default) or in a sub folder?

You can try to create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox