I've recently done a little experiment and took a look at the first few websites which I have ever visited with my current Firefox profile and wrote them down. I was also a little bit confused, because I don't think that the things I apparently first ever visited in the Firefox history viewer were actually what I first ever visited.

A month or so later, I took another look at the first few websites I visited in the Firefox history viewer, but they were something completely different this time.

I'm very confused as to why this happens. Does Firefox automatically delete history entries which have a certain age?

For clarification:

Yes, I did click "Older than 6 months", and yes, I am also aware that history entries, which I visit again in the future automatically get moved to the top of the history list. I have also entered the URLs that I wrote down in the search box, but no results. So I assume Firefox deletes history?

EDIT: And if the answer is yes, is there a way to make it so that Firefox never deletes history entries? (I know it affects performance, but I'd rather keep all of my history entries permanently)

  • Yes, it does. I think this is configurable in about:config. – Bob Mar 19 '16 at 12:25
  • Go to about:config. Read and accept the warning, then find "browser.history_expire_days.mirror". I don't keep history that old, but depending what it is set on, you could try setting it to something >180 days. Don't know if there is an upper limit though. – user3169 Mar 20 '16 at 4:45
  • @user3169 that pref is obsolete for a few years now... – bernstein Jun 12 '16 at 21:17

Moderators at Mozilla suggested the following:

You would have to create a new integer pref with the name places.history.expiration.max_pages and set the value of the pref to the desired number of history items like you can see in my post above. Preferences can be created on the about:config page via the right-click context menu: New -> Integer


AFAIK there is only one setting in about:config that seems to control this: places.history.expiration.transient_current_max_pages. On my machine it's set to 104858 (it says 'user set', but i have never and seem to be unable to change it's value). Interestingly in practice, that amounts to less than 6 months!!! according to this blog entry it's supposedly all my machine can handle (sure skylake, 32gb ram & 1tb ssd can't handle more ;-))...

Assuming each history entry takes about 100 bytes (average page title + url + visited timestamp + visit counter (in my case)) that caps history at about 10MB, but i'd rather it taking 10GB and retaining more than 5 years...

real shame as this essentially makes firefox much worse than i ever thought it was...


Firefox will act based on the setting set in Privacy (copy/paste this in the location bar about:preferences#privacy)

From the History, spot Firefox will and choose Remember history from the drop-down list. This should keep your browsing activities.

From the Location Bar, tick a mark in History. This should display visited URLs when your typing matches an entry in the History.

  • I already have Firefox set to "Remember history", but yeah... Still seems like it deletes entries which are too old. – Minegem Mar 19 '16 at 12:37
  • if it forgets all history, it only means that someone has cleared it. – Sanny Mar 19 '16 at 13:08

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.