With Firefox 67 you’ll be able to run different Firefox installs side by side by default.

Supporting profiles per installation is a feature that has been requested by pre-release users for a long time now and we’re pleased to announce that starting with Firefox 67 users will be able to run different installs of Firefox side by side without needing to manage profiles.

What are profiles?

Firefox saves information such as bookmarks, passwords and user preferences in a set of files called your profile. This profile is stored in a location separate from the Firefox program files.

More details on profiles are can be found here.

What changes are we making to profiles in Firefox 67?

Previously, all Firefox versions shared a single profile by default. With Firefox 67, Firefox will begin using a dedicated profile for each Firefox version (including Nightly, Beta, Developer Edition, and ESR). This will make Firefox more stable when switching between versions on the same computer and will also allow you to run different Firefox installations at the same time:

You have not lost 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 67, Firefox installations will now have separate profiles. This will apply to Nightly 67 initially and then to all versions of release 67 and above as the change makes it way to Developer Edition, Beta, Firefox, and ESR.

What are my options?

If you do nothing, your profile data will be different on each version of Firefox.

If you would like the information you save to Firefox to be the same on all versions, 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 versions of Firefox. You also get additional benefits like sending tabs and secure password storage. Get started with Sync here.

You will not lose any personal data or customizations. Any previous profile data is safe and attached to the first Firefox installation that was opened after this change.

Users of only one Firefox install or users of multiple Firefox installs who already had set different profiles for different installations will not notice the change

We really hope that this change will make it simpler for Firefox users to start running Nightly. If you come across a bug or have any suggestions we really welcome your input through our support channels.

What if I already use separate profiles for my different Firefox installations?

Users who already have created manually separate profile for different installations will not notice the change (this has been the advised procedure on Nightly for a while).