How To Disable Prefetching in Firefox & Epiphany

By | 2008/03/20

update: I have also found that prefetching is active in the Epiphany browser as well. The instructions to de-activate it are the same, see below.

I recently found out that Firefox has a feature called “prefetching” that tries to pre-download items that it suspects you might click on soon.  This could help in pre-downloading content that you would visit next (ie; it is linked on the page you are visiting therefore you might access it next), but it can also have the nasty negative effect of wasting your bandwidth on items you don’t ever want.  This can also download cookies from sites you haven’t visited, etc.  Seems like a nasty feature to me!

I also found that this prefetching feature will cause your connection to the (and a few other sites) to be refused if you are also going through a squid proxy.  So, this is a quick suggestion on how you can disable prefetching in Firefox.

Disable Prefetching in Firefox

In your browsers address window enter the address:


This will pull up your browser settings (in FF3 it will warn you that there be dragons ahead!  Just accept the warning.)  You’ll now want to search for the following string, which you’ll toggle off:


To toggle off this setting simple double-click the listing and it will set to false.  Prefetching items that you might download is now disabled.  Your machine will now kindly only download the content, cookies and images that you actually access directly.

10 thoughts on “How To Disable Prefetching in Firefox & Epiphany

  1. John L. Clark

    Thanks very much for this tip; I had no idea that Firefox even performed this functionality, and I’m glad that I do, now (and it very quickly was turned off).

  2. Jason

    I don’t mean to take people away from your site but look here for a good discussion of the pros and cons of prefetching and why’s it’s enabled by default: . There are a lot of comments so just ctrl+F prefetching and read.

  3. David Dallet

    Thanks for the info! I knew for a long time what prefetching mean but I couldn’t even suspect that firefox does it. Sure it may have advantages, but I don’t want it (even if I have no traffic limitation problem in my country).

    Thanks again,


  4. Conor

    Hm, I’ve actually seen FasterFox blasted for prefetching functionality from the server admin standpoint. It’s just absurdly wasteful of bandwidth, although it might have negligible benefits for browsing performance.

    Such griping, though, could be likened to websites crying foul when the Google 1.0 crawler made its initial rounds around the web.

  5. Vadim Peretokin

    I don’t think it’s a nasty feature at all. Without numbers (hit/miss, how much stuff was loaded faster because of this) you really can’t blame it.

    I myself will be keeping it – I have an OK bandwidth limit, and would like faster browsing.

  6. troll

    Thanks. I had forgotten about this feature. Very handy indeed when I open some 300 tabs simultaneously, I have been wondering why it has been bogging the browser down.. 😀

  7. mlissner

    You should really mention that prefetching doesn’t run around downloading EVERYTHING all haphazard-like. It only downloads links that are specifically coded to be prefetched. So, it’s not like you could go to a safe website, and your computer is going to be downloading information from a piracy one, or something.

    From what I can tell, this is a useful feature, since it will only download links that have been specifically set up to be downloaded. This would probably negate worries of prefetching from other domains than the one you’re on. It’s possible, but there isn’t any motivation for it really…seems like a useful feature to me.

  8. Sunnz

    Exactly why would this cause problem with Squid?

    I have been having problems lately that Firefox keep on having problems with Squid, so I googled and I think this is the cause… but why would it be a problem with Squid?

    Prefetch sounds like a good feature to me, so I’d like to tweak things to have it to work with Squid if possible.

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