This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

I can't reset the browser.cache.frecency_experiment setting

  • 6 replies
  • 4 have this problem
  • 2 views
  • Last reply by cor-el

more options

I tried pretty much everything from https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save http://kb.mozillazine.org/Preferences_not_saved Everything involving prefs.js and user.js. Obviously I'm not interested in reseting my Firefox completely. My system is clean according to Comodo CCE, MBAM and adwcleaner.

Anyway, when I'm resetting the setting in about:config it keeps resetting to user set 4 OR 3. I recall I've set it manually to some value months ago.

I tried pretty much everything from https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save http://kb.mozillazine.org/Preferences_not_saved Everything involving prefs.js and user.js. Obviously I'm not interested in reseting my Firefox completely. My system is clean according to Comodo CCE, MBAM and adwcleaner. Anyway, when I'm resetting the setting in about:config it keeps resetting to user set 4 OR 3. I recall I've set it manually to some value months ago.

All Replies (6)

more options

Hello effgo, any luck if you change the value to -1 ? (no experiment)

https://mxr.mozilla.org/mozilla-release/source/netwerk/cache2/CacheObserver.cpp#181

thank you

more options
more options

ideato said

Hello effgo, any luck if you change the value to -1 ? (no experiment) https://mxr.mozilla.org/mozilla-release/source/netwerk/cache2/CacheObserver.cpp#181 thank you

-1 did it. Isn't it a bug though? Doesn't the 'experiment' mean it's an unstable, experimental feature? If yes, then the 'Reset' command should set it to "-1". Should I file a bug report?

more options

I think that it has to do with cache management and deciding whether to decay cache entries (i.e. HalfLife) The default to check this is 6 hours and can be increased to 50 days.

1759 // Play with different values of the decay time and get telemetry,
1760 // 0 means to randomize (and persist) the experiment value in users' profiles,
1761 // -1 means no experiment is run and we use the preferred value for frecency (6h)
1762 pref("browser.cache.frecency_experiment", 0);
89 // The half life used to re-compute cache entries frecency in hours. 90 pref("browser.cache.frecency_half_life_hours", 6);

Modified by cor-el

more options

Thanks for the info but right now I'm interested more in a stable experience.

more options

You can try to set the pref to -1 (or 1: 6 hours) on each Firefox start via a user.js file.

user_pref("browser.cache.frecency_experiment", -1);

You can also check the browser.cache.frecency_half_life_hours pref.