Dedicated profiles per Firefox installation

This feature requires Firefox version 67 and up.

What are profiles?

Firefox saves information such as bookmarks, passwords and user preferences in a set of files called a profile. This profile is stored in a location separate from the Firefox applicationprogram files. More details on profiles can be found here.

What changes are we making to profiles in Firefox 67?

Some users have multiple installations of Firefox, each in separate applicationprogram folders. These separate Firefox installations previously shared a single profile by default. Beginning with Firefox version 67, Firefox will use a dedicated profile for each installation of Firefox (including Nightly, Beta, Developer Edition, and ESR installations) . This will make Firefox more stable when switching between installations on the same computer and will also allow you to run different Firefox installations at the same time.

  • You will not lose any personal data or customizations. Any previous profile data is saved and associated with the first Firefox installation that was opened after this change.
  • Starting with Firefox version 67 Firefox installations will have separate profiles. This will first apply to Nightly version 67, then make its way to version 67 of Developer Edition, Beta, Firefox, and ESR.


Tip: To see what version of Firefox you're on, see Find what version of Firefox you are using.

What are my options?

If you do nothing, your profile data will be different on each installation of Firefox. If you would like the information you save to Firefox to be the same on all installations, you can use a Firefox Account to keep them in sync. Sync is the easiest way to make your profiles consistent on all of your installations of Firefox. You also get additional benefits like sending tabs and secure password storage. Get started with Sync here.

Can I change which Firefox install uses my previously shared profile?

Yes. You can use the profile manager to change which profile is associated with each installation of Firefox. Directions on how to use the profile manager are available on this support page.

I am a Sync user, will my saved data still remain synced?

Yes. Once you sign in to your Firefox Account on Firefox, any data saved to Sync from other installation of Firefox should appear.

What happens to my profile if I downgrade to a previous version of Firefox?

You’ll have to create a new profile to avoid corruption issues.

Starting with Firefox version 67 each Firefox installation requires a separate profile. Downgrading won’t cause the loss of any personal data or customization on the later version, and any previous profile data is saved and associated with the first Firefox installation opened after the change.

Downgrade protection can be overwritten by launching Firefox through the command line with the --allow-downgrade parameter.

I already use separate profiles for my different Firefox installations

If you have already manually created separate profiles for different installations, you will not notice the change (this has been the recommended procedure on Nightly for a while).

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