I went to facebook yesterday evening and it struck me that I had to type in my password to be able to log in (normally I'm already signed in or have autocomplete do it for me). I went to my email providers website (google) soon after that and discovered I had to log in to that too.

Just today I went to Twitter and again I had to log in.

I use Mozilla Firefox and I am just curious as to why I am suddenly signed out. This is on my laptop, and I use Firefox exclusively on both of my PC's. The desktop hadn't been used in some time so I think maybe when I used it for a few hours the other day maybe something I did caused my sign out.

Normally I log in via autocomplete. Logging in was no issue, I either remembered my passwords or looked it up in Firefox but I'm just concerned someone could have accessed my accounts. I really doubt someone did that but I have no other explanation, except maybe Mozilla updated Firefox in some way and that caused my signout??

4 Answers 4


The only reason I could think of is if you (inadvertently) cleared your recent browser history, in particular the active logins (perhaps cookies as well). By deleting that you would delete the list of websites you are currently logged into, including your access details (data that your browser stores locally in your computer). Therefore you will have to log back in as soon as a particular website needs your credentials again.

You can control which elements of the history can be deleted by going to History -> Clear Recent History... and checking/unchecking the history details (and optionally modify the time range to clear, too). Said that, it might be a could practice to delete the browser cache/history regularly: with those options you are in control of what elements should be cleared and when.

If now your problem occurs frequently, the option to delete the Firefox history whenever Firefox closes might be on. Go to Edit -> Preferences -> Privacy and make sure the checkbox Clear history when Firefox closes is unchecked (or configure it according to your needs through the Settings button next to it).

In case you're worried someone else might have accessed your account, the websites you mentioned should have (Google has) the ability to log and list your recent account activity. For example, you could check the recent activity of your devices connected to your Google Account and spot any suspicious operation.

  • Well that is really odd because I think that I have not touched my history settings in ages. Unless of course I accidentally hit the "clear recent history" option in the history menu sometime this weekend... which is not all that impossible because I have a psychological "tick" where I left/right click constantly and without control. Hmmm... Thank you!
    – jayftw
    Commented May 25, 2015 at 13:47
  • @Braineeee You're welcome. Another reason could be that Firefox deleted that history data because of a bug in its update process, but I doubt it. I don't think this is worth to mention in my answer, but at least it's tracked here in the comments as a remote possibility.
    – mguassa
    Commented May 27, 2015 at 5:53

There are two reasons that I can think of:

  1. You or someone else cleared all the cookies from your browser.
  2. You currently are in private browsing mode. (highly unlikely)

In the latter case just switching back to normal mode will do the needful. Press Ctrl + N to do that.

  • Welcome to Superuser. Your answer is good, but you could improve it by adding the steps needed to exit private browsing mode.
    – Trav
    Commented May 25, 2015 at 14:31

Firefox and ALL of the mentioned sites offer both mfa --multi factor auth and session timeouts either or both could in addition to above mentioned cookie issues cause described behaviour and google / ff both ha recent updates that changed defaults for mfa


it's because you have deleted your cookies or any other program like ccleaner has deleted your cookies.

  • This was already covered by chetan's answer. Each answer should contribute a new solution to the question.
    – fixer1234
    Commented May 26, 2015 at 1:00

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