Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

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

Lost all saved login data from Sync and local profile.

  • 3 replies
  • 3 have this problem
  • 7 views
  • Paskiausią atsakymą parašė cor-el

more options

Hello, I've discovered that all my saved passwords are gone. I tried to reinstall FF ( stable, normally I use beta ) with removing local Mozilla folders and add it again to Sync. Seems there is no saved data. I found logins.json.corrupt file which is around 200 KB but I can't swap it with logins.json - this don't change anything. Is there any option to recover local or Sync login data?

What's important and I think it might be a cause of all this situation - I was testing FF Nighly 57a1 ( zip version ) and maybe this destroyed my data. Last chance for me is to recover that data from second computer ( before it sync ) but I'm worried that it has also corrupted data, because this is the place where I was testing that alpha version.

UPDATE: I've managed to recover all my data from whole PC backup ( 1 week ago - but no changes was made so it's ok ) - anyway it would be nice if You allow people to recover their data.

Greetings, Mike

Hello, I've discovered that all my saved passwords are gone. I tried to reinstall FF ( stable, normally I use beta ) with removing local Mozilla folders and add it again to Sync. Seems there is no saved data. I found logins.json.corrupt file which is around 200 KB but I can't swap it with logins.json - this don't change anything. Is there any option to recover local or Sync login data? What's important and I think it might be a cause of all this situation - I was testing FF Nighly 57a1 ( zip version ) and maybe this destroyed my data. Last chance for me is to recover that data from second computer ( before it sync ) but I'm worried that it has also corrupted data, because this is the place where I was testing that alpha version. UPDATE: I've managed to recover all my data from whole PC backup ( 1 week ago - but no changes was made so it's ok ) - anyway it would be nice if You allow people to recover their data. Greetings, Mike

Modified by impact

All Replies (3)

more options

Yes, using Firefox 55 or above and then going back to Firefox 54 can result in lost data. Sorry that you had that issue, but using pre-release builds when you aren't very experienced with pre-release builds sometimes causes data to be lost. Nightly used to be named Minefield and the logo was a globe with a lit explosive sticking out the top for that reason.

more options

the-edmeister powiedział

Yes, using Firefox 55 or above and then going back to Firefox 54 can result in lost data. Sorry that you had that issue, but using pre-release builds when you aren't very experienced with pre-release builds sometimes causes data to be lost. Nightly used to be named Minefield and the logo was a globe with a lit explosive sticking out the top for that reason.

Ok, but it does not solve the issue. Is there really no option to get login data back ( sync / local fixing )? In my case it's not a problem because I had backup, but i bet that someone might have a real pain if that happen.

Modified by impact

more options

Did you check the logins.json file to see in what way the file is corrupted? You can open the logins.json file in a Firefox tab and see if the JSON viewer can parse this file.

Did Nightly crashed?


Note that you should always use a separate profile when you use different Firefox versions and especially when using unstable Nightly and beta builds.

See: