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Firefox 12 incorrectly caching pages


After upgrading from Firefox 11 to 12 I'm having serious problems with Firefox over-caching pages.

For example if you: Go to a URL where you can enter comments. If after comments are entered you are sent back to the same URL Firefox is showing the old page (without your new comments). You have to do a refresh to see the new page (with the new comment)

Even if the page has PHP headers: header('Cache-Control: no-cache, no-store, must-revalidate'); header('Pragma: no-cache'); header('Expires: 0');

Firefox ignores this too.

Chosen solution

Firefox 13 is out and the fix for this issue is included in the release. Please update to the latest release version of Firefox if you are still having this issue.

Read this answer in context 6

Additional System Details

Sites Affected


Installed Plug-ins

  • Shockwave Flash 11.2 r202
  • Adobe PDF Plug-In For Firefox and Netscape 10.1.3
  • Version
  • Google Talk Plugin Video Accelerator version:
  • Picasa plugin
  • Google Update
  • 4.1.10111.0
  • 20-20 3D Viewer for IKEA - Mozilla Plug-In v5.0.93.0
  • Unity Player 3.4.1f5
  • npFFApi
  • Logitech Device Detection
  • The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.
  • NPRuntime Script Plug-in Library for Java(TM) Deploy
  • IE Tab Plug-in for Mozilla/Firefox
  • EA SPORTS Game Face Plugin
  • 1.9.0042.0
  • Office Plugin for Netscape Navigator


  • User Agent: Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20100101 Firefox/12.0

More Information

maxchaos 0 solutions 3 answers

Firefox cache has never worked for me. Everytime I view a website/webpage i've viewed before the network connection starts up and doesn't even LOOK for a cache. It seems kinda pointless having that option when it doesn't work. LOLZ. If I have seen a page ever before, why not just use it unless the person requests a refresh? Why waste all that bandwidth?

Taco_X 0 solutions 8 answers

lol - i wish it didn't work for me. i would love for ff to force a new page anytime i reopen my browser or refresh a page. not worried about bandwidth at all. i seldom browse from my phone which would be the only time i would have a thought about bandwidth.

btw, i'm on xp - is that a factor in all this?

Modified by Taco_X

maxchaos 0 solutions 3 answers

Well, consider youtube videos. Lets say you've watched a 2 hour clip. You really expect people to want to download the full thing again to watch? Seriously. If you are not concerned with bandwidth, then why would you even bother commenting? It seems your reality is not the same as the majority of people out there getting screwed by ISP. Especially people using mobile broadband.

Taco_X 0 solutions 8 answers

it should be a feature you can turn on or off then. why the hell should you reply i could equally ask you.

[Personal attack removed by moderator. Please read Forum rules and guidelines, thanks.]

Modified by Chris Ilias

  • Top 10 Contributor
2383 solutions 21079 answers

Hi maxchaos, by default Firefox will cache any content the server instructs it to cache, and will not cache content the server instructs it not to cache. Youtube videos unfortunately are not supposed to be cached.

Hi Taco_X, you can disable caching if you prefer. There might be a way to do this in the options dialog, but it might be more straightforward to use the about:config preferences page to make that change.

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the filter box, type or paste cache and pause while the list is filtered

(3) Double-click browser.cache.disk.enable to toggle the value from true to false. Firefox also does some in-memory caching. The preference for that is browser.cache.memory.enable.

Taco_X 0 solutions 8 answers

thanks for the tip for disabling caching. i would vote that your comment helps but i don't have that option.

maxchaos 0 solutions 3 answers

jscher2000, this begs the next question. Why not cache video content? Why is the question. If obviously it could make things easier. Why not?

  • Top 10 Contributor
  • Moderator
10780 solutions 97024 answers

YouTube sends its video content currently in small chunks to the video player via a GET request and throttling at low speed, so you will only get file fragments and not a complete file in the cache.