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What can happen if i open my main-version profile with a pre release version, like Nighty?

  • 4 replies
  • 1 has this problem
  • 8 views
  • Last reply by ledgeri

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After i understood how the profile-system, and installation-system works (https://support.mozilla.org/en-US/questions/1263567 ) it cleared to me, i need to have 3 installation, and 3 profiles to work as i wish: one main profile, one open profile, and one dummy, to manage automatic browser-opening buttons from other programs.

Currently i have 5 installation (2 main branch, 1 beta, 1 dev, 1 nighty), and severeal profiles.

What am i risking, if E.g. i open my main branch (with several addons, settings) with a Nighty, as step A? What am i risking if i reopen the step A profile again, with the main branch?

What can i loose permamently, what can i loose recoverable, what can be annoying, what will work flawlessly?

After i understood how the profile-system, and installation-system works (https://support.mozilla.org/en-US/questions/1263567 ) it cleared to me, i need to have 3 installation, and 3 profiles to work as i wish: one main profile, one open profile, and one dummy, to manage automatic browser-opening buttons from other programs. Currently i have 5 installation (2 main branch, 1 beta, 1 dev, 1 nighty), and severeal profiles. What am i risking, if E.g. i open my main branch (with several addons, settings) with a Nighty, as step A? What am i risking if i reopen the step A profile again, with the main branch? What can i loose permamently, what can i loose recoverable, what can be annoying, what will work flawlessly?

Chosen solution

Tyler Downer said

Using multiple channels on the same profile is never a good idea. There can be bugs in nightly that break your profile, or there could be things in nightly that change your profile that then make it unreadable by an older version.

Thanks.. it makes sence... So playing for safety, i will use only main branch ones only.

Thank you!

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All Replies (4)

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Using multiple channels on the same profile is never a good idea. There can be bugs in nightly that break your profile, or there could be things in nightly that change your profile that then make it unreadable by an older version.

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Chosen Solution

Tyler Downer said

Using multiple channels on the same profile is never a good idea. There can be bugs in nightly that break your profile, or there could be things in nightly that change your profile that then make it unreadable by an older version.

Thanks.. it makes sence... So playing for safety, i will use only main branch ones only.

Thank you!

Modified by ledgeri

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Note that Nightly and Developer Edition and Beta builds will refuse to use a profile that has been used by anther Firefox versions.

If you have one profile for the current Firefox release and that profile is set as the default profile then external links should use this profile. If there are still problem the use a xxxxxxxx.default-release profile and transfer your data to this profile and remove other profiles from the Profile Manager (you may want to keep the files for a few weeks or possibly back them up).


Firefox 67 and later can use a dedicated profile for each of the Firefox update channels and will lock the profile, so it can only be used by Firefox in a specific installation folder. For Release versions this profile would be a xxxxxxxx.default-release profile, profiles used in older Firefox versions usually used a xxxxxxxx.default profile (a refresh adds a time stamp).

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cor-el said

Note that Nightly and Developer Edition and Beta builds will refuse to use a profile that has been used by anther Firefox versions. If you have one profile for the current Firefox release and that profile is set as the default profile then external links should use this profile. If there are still problem the use a xxxxxxxx.default-release profile and transfer your data to this profile and remove other profiles from the Profile Manager (you may want to keep the files for a few weeks or possibly back them up).

Firefox 67 and later can use a dedicated profile for each of the Firefox update channels and will lock the profile, so it can only be used by Firefox in a specific installation folder. For Release versions this profile would be a xxxxxxxx.default-release profile, profiles used in older Firefox versions usually used a xxxxxxxx.default profile (a refresh adds a time stamp).

As i mentioned i have several profiles. Before the Firefox 67, i already had some. I started using them with profile manager, what asks me wich one i want to use in the current session. I used to use that, as a preventive solution against loading a whole stored session, when accidently clicking onto links, in programs like game clients, what are opening the the default browser. I kept the profile manager since then, i like to use it

The problem with the default browser opening external links method is it locked to the installation, and not to the profile, or something else. This means, if i am opening my default browser installation, to check something in private mode and for that i select my main profile at session start, and an external request arrives, it does not opening in the private window. It launches a new window, with the stored session, what breaks my flow... Also there is no option, to start the program in provate browsing occasionly, when an external request triggers it....

In a situation, where i have 2 installation, but 2+ profiles, if i close both install on the same profile, and i relaunch one install with that, if i need to access an other profil i can not open it right away, because the second installation opens the running profile , not showing the profile manager window" Again,only if both was closed on that, before reopening with one again.

To prevent those i need the third install, to have that .exe, the default browser, and the third profile to keep the existing ones untouched as possible...


Note that Nightly and Developer Edition and Beta builds will refuse to use a profile that has been used by anther Firefox versions.

Should this include themselfs too? I just tried, and i was able to open with the nighty install, the Beta-default profile, without any message being promted... (some message was promted at first startup, that is true, but it is not a hard refuse!)

Anyways in the current methodology of firefox, i need 3 installs, and 3 profiles, for 2 profiles in main use, to get what i want ,done as i want -i have no problem with that! And to be surely safe i will need to use main branches only - no problem either!

Thank you for helping, again!