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how to deal with new Firefox (11/6/20)

  • 2 replies
  • 1 has this problem
  • 10 views
  • Last reply by cor-el

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I opened Firefox today and all of my tab, bookmarks, logins, etc. were lost. Here is the message I received: "Changes to your Firefox profile What changed?

This installation of Firefox has a new profile. A profile is the set of files where Firefox saves information such as bookmarks, passwords, and user preferences.

In order to make it easier and safer to switch between installations of Firefox (including Firefox, Firefox ESR, Firefox Beta, Firefox Developer Edition, and Firefox Nightly), this installation now has a dedicated profile. It does not automatically share your saved information with other Firefox installations.

You have not lost any personal data or customizations. If you’ve already saved information to Firefox on this computer, it is still available in another Firefox installation."

My question: I have not logged into my Firefox "profile" for a long time, but have been using the browser daily. It appears that my bookmarks and saved logins have not been saved since I last logged in (not sure when this was). So, can I use some of my history files to restore my saved bookmarks and logins from my last session? If yes, how do I do this? I am not a Firefox whiz. I have located the app data folder and have a lot of jasonlz4 files that I could conceptually use for this, but I don't know how. thanks for your help!

I opened Firefox today and all of my tab, bookmarks, logins, etc. were lost. Here is the message I received: "Changes to your Firefox profile '''What changed?''' This installation of Firefox has a new profile. A profile is the set of files where Firefox saves information such as bookmarks, passwords, and user preferences. In order to make it easier and safer to switch between installations of Firefox (including Firefox, Firefox ESR, Firefox Beta, Firefox Developer Edition, and Firefox Nightly), this installation now has a dedicated profile. It does not automatically share your saved information with other Firefox installations. You have not lost any personal data or customizations. If you’ve already saved information to Firefox on this computer, it is still available in another Firefox installation." My question: I have not logged into my Firefox "profile" for a long time, but have been using the browser daily. It appears that my bookmarks and saved logins have not been saved since I last logged in (not sure when this was). So, can I use some of my history files to restore my saved bookmarks and logins from my last session? If yes, how do I do this? I am not a Firefox whiz. I have located the app data folder and have a lot of jasonlz4 files that I could conceptually use for this, but I don't know how. thanks for your help!

All Replies (2)

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Hi mokunz, did you start Firefox the same way as you did yesterday, using the same shortcut or other method?

Note: The term profile refers to a folder on disk and not your Firefox Account. A profile can be connected to an account, or not.

Before going further, if you haven't restarted Windows since this problem started, I suggest doing a regular shut down and restart of Windows to release any locked files or folders.


Next, could you check some details about your current Firefox version. Open the Troubleshooting Information page. Either:

  • "3-bar" menu button > "?" Help > Troubleshooting Information
  • (menu bar) Help > Troubleshooting Information
  • type or paste about:support in the address bar and press Enter

In the first table, what do you have in these places (I'll give you mine for comparison):

  • Version: 82.0.2
  • Update Channel: release
  • Application Binary: C:\Program Files\Mozilla Firefox\firefox.exe

On that last one, if you have had Firefox installed for a long time, it may be here instead:

C:\Program Files (x86)\Mozilla Firefox\firefox.exe

Sometimes for unknown reasons you end up with a dual install in both of those folders, with the shortcut pointing to the newer one but Windows opening external links in the older one, and problems updating. If that sounds at all familiar, please check on disk whether you have installs in both program folders so we can sort that out first. Please don't delete any folders without further advice!


Here is another page to check:

Profile Manager Page

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

This page should list at least one profile and could list many. (Each profile has two folders and one or more buttons. Do not use any Remove buttons!)

The profile that Firefox is currently using will have this:

This is the profile in use and it cannot be deleted.

Do you have another profile listed here with default in its name? If so, you can check whether it is the one you were using recently by clicking its Launch profile in new browser button.

If it isn't what you want, simply close that new window.

If it IS what you want, back on the about:profiles page, click the Set as default profile button for that profile so Firefox uses it automatically at the next startup.

Firefox won't launch a profile created in a later version, but unless you have been using Beta, Developer, or Nightly, that shouldn't be a problem for Firefox 82.0.2.

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