Profiles do not share personal data like username and password unless you connect the profiles to the same Sync account. The Firefox Password Manager stores the logins in logins.json in the Firefox profile folder and doesn't share this data with other profiles.

• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

I don't know how LastPass works, but if you connect to LP using the same credentials assuming it stores its date on a cloud server then this likely means that LP makes all logins available to all devices.

So I have three profiles for different things (one is another person in the house using their own LastPass). If I log into LastPass on MY profile, it ALSO logs it into last pass on THE OTHER PROFILES. If he logs into HIS lastpass account on HIS profile, it changes MY profile lastpass session to HIS ACCOUNT.

It is ABSOLUTELY sharing data across profiles. How do I STOP this?!

This is entirely unacceptable and RIDICULOUS. There is NO reason why two profiles shouldn't be able to run and each be 100% independent from each other.

Looks like running them in separate instances and using the -no-remote option solves this problem... as does running Firefox Portable. Not the most elegant or practical solution... but it IS a solution. :)

Correction, it's NOT solving it.

When you visit about:profiles in the address bar, do you see three different profiles? Is the "Root Directory" for each profile different? Is the one labelled "This is the profile in use and it cannot be deleted" different when you launch each profile in the normal way?

Yes, they were/are all different profiles with their own directories and everything- something I did specifically on purpose to isolate each person's user data from each other. This is from the profiles ini file... the full path is C:\Users\[username]\AppData\Roaming\Mozilla\Firefox\Profiles\...

[Profile1] Name=Kaleb IsRelative=1 Path=Profiles/cvtywzbs.Kaleb [Profile0] Name=Zor IsRelative=1 Path=Profiles/z7sxcbj8.Zor [Profile2] Name=Angel IsRelative=1 Path=Profiles/fy75czwv.Angel

It was vexxing b/c if one of these were launched and that user signed into LastPass (that was the biggest concern, honestly)... and someone else got on their profile, the new launched one grabbed the other profile's LP login session and the extension showed someone else's vault. Example: Angel is on doing something and logged into his LastPass. Kaleb gets on in HIS profile and logs into his. Angel comes back and sees LP is now showing logged as Kaleb (while on ANGEL'S profile)... it's so... weird.

As for "is it different"... what do you mean when I launch it in another way? I generally was doing it from the profile manager. When more than one are logged in on their profiles, it does show them both/all to be "in use" and not able to be deleted. And only the last one launched can see about:profiles... It still doesn't explain, however, why ONE profile's actions would bleed over to the others that are active. It shouldn't do that. Each should be able to maintain login credentials and activities for that profile and its own operation entirely unaware of the other profiles, much less bleeding over into them.

If this is about running Firefox on the same device, but under different Windows user accounts then this is to be expected as in that case you merely open a new Firefox instance on the same Firefox profile. Using '-no-remote' will allow to open separate Firefox instances each with their own profile.

If you click a login verification link in an email app, it will open in the default profile which may belong to someone else and contaminate it with your login cookie. To avoid this, you can unassign the default profile so it will ask you which one to use each time. It may help to give each profile a different theme to make them easier to visually distinguish.

Using -no-remote prevents external links from being opened in the profile altogether, you need to manually drag and drop or copy and paste them into the appropriate profile.

-no-remote ALSO forces a new instance of Firefox, so every profile launched this way is isolated to it's own system/CPU instance and not connected to the other running ones. It basically allows Firefox.exe to run several times, with each profile being it's OWN process. The reason I use that instead of "new-instance" is that doesn't work on Windows (though does on my Linux laptop)... But no-remote accomplishes the same thing in this sense.

The above is per the Mozilla wiki about it- and where I learned the command was a possible option and solution (which it turned out being) https://wiki.mozilla.org/Firefox/CommandLineOptions

I think the profiles have their own themes anyway- just a byproduct of why the exist... and b/c it IS easier to know which is up at the moment.

Profiles are already fully isolated by default. -no-remote used to be needed to run multiple profiles at once but this is no longer the case. When you try to open a profile more than once, a new window is created for the existing running profile. -no-remote prevents this and external links with the message "Firefox is already running, but is not responding".

"Profiles are already fully isolated by default." <--- this simply isn't true in USE... in theory, sure... and it SHOULD BE. But I am experiencing this exact behavior that proves that's NOT true. I can create different profiles and logging into a site, or extension on ONE, does so to ALL profiles. It's ridiculous that this "bleedover" is happening.

The idea we can't separate profiles to NOT share common things without different windows logins is absurd. Chrome does this- different profiles can be launched and have different settings and logins and NEVER SEE the other profiles information.

Point in case- three different FF profiles have LastPass extension installed. If I log into LP on my main one, the OTHER PROFILES log into that SAME LASTPASS... despite that they had their own account logged in. If I log in to the appropriate LP on that profile, ALL OF THEM share the same LP login. Why?! Why does FF make ALL profiles extensions share that information across ENTIRELY SEPARATE profiles?!

More importantly, how do I solve this?! There's NO REASON this should be happening... I've wiped out and recreated profiles FOUR TIMES now and it never fixes this problem. Profiles should be 100% isolated from each other- that's then ENTIRE POINT of a separate profile.

And fwiw, this is why I am not using it as my daily driver despite wanting badly to get off Chrome... this isn't something that should require a lot of work or hunting for answers to. This should just work out of the box... it's very vexxing... and I'm a computer nerd and have done this stuff for years (not on FF since they changed the UI years ago to limit controlling everything about how it looked and operated, until recently trying to come back).

Any help on how to totally isolate profiles would be very very appreciated.

Why does FF make ALL profiles extensions share that information across ENTIRELY SEPARATE profiles?!

Any help on how to totally isolate profiles would be very very appreciated.

At the moment Firefox creates an independent profile, it shares zero data with any other profile. And it should remain separate unless: you sign in to a Firefox/Mozilla Account in that profile which already has data from another profile or installation. In that case, Sync kicks in and starts merging the data in that profile with the other desktop Firefox installations/profiles connected to the same account.

You may wonder why Firefox Sync does not detect that it's a different profile and partition the data. As far as Sync is concerned, all desktop installations signed into Sync should have the same data, whether on the same computer or on different computers. So you cannot use Sync if you do not want any data shared into/out of a profile.

Good news: you don't need to sign Firefox into an account. Just disregard that option like back in the day.

If did you want to use Sync only for some data, like bookmarks, you could trim down the selection of what syncs. See: How do I choose what information to sync on Firefox? I think you would first need to make that change in one or all of your existing profiles so that it gets inherited by the new one(s).

My alternate theory, if Sync is not to blame, is that the LastPass extension is doing it.

The LastPass extension has a "Share login state" setting that determines whether you can sign in to different accounts in the same browser, or whether they get switched. See the following article for steps to change this setting:

Can I log in to multiple LastPass accounts on the same computer?

It mentions that this is automatic between Chrome profiles, but it seems you need to manually change the setting for Firefox.

My alternate theory, if Sync is not to blame, is that the LastPass extension is doing it. .... It mentions that this is automatic between Chrome profiles, but it seems you need to manually change the setting for Firefox.

I'll try that, but I still have a SERIOUS issue with why Firefox will share this across profiles even if they are not running at the same time- WHY does it allow this to be bled across profiles? It's a website login basically... there's NO REASON this should be happening for isolated entirely separate profiles... yet it does... and apparently ONLY on Firefox. That seems to indicate something in ITS handling of profiles is not isolating them appropriately. If an extension on one profile can forcefully log someone in/out of something on other ones... that's a problem. And if it LP is doing it, what OTHER things is this happening with that we haven't stumbled on yet.

As you note- Chrome doesn't do this. What ONE profile does is ENTIRELY separate from what another one does. Firefox, years ago, was the same. Why is it not that way now?

At the moment Firefox creates an independent profile, it shares zero data with any other profile. And it should remain separate unless: you sign in to a Firefox/Mozilla Account in that profile which already has data from another profile or installation. In that case, Sync kicks in and starts merging the data in that profile with the other desktop Firefox installations/profiles connected to the same account.

They have their own sync login specifically to prevent this problem. None of the profiles share a FF/Mozilla sync login. I considered that early on. But also, given why I am making these profiles, it made sense to NOT have them share one sync (I have DID - mult personality- and keeping each part of "us/me" on our own thing for our own interests and favorites, etc). I want to have each profile, using it's own sync (as they do), to NOT be impacting the other profiles... And worth noting, NOTHING ELSE is changing with this, just the LP login (as far as I can tell anyway). Preferences, settings, logins, extensions installed (which vary profile to profile). It's just that ONE problem- and I can't understand why FF would allow ONE extension to bleed over through all profiles instead of entirely isolating it.

I can't understand why FF would allow ONE extension to bleed over through all profiles instead of entirely isolating it.

Normally, add-ons cannot connect with other programs on your computer. However, if you look at the permissions for the LastPass extension (listed in the left column), you can see it requires "Exchange messages with programs other than Firefox." By design, it interoperates with the LastPass binary component on your system, which presumably enables some useful functionality as well as this annoying feature. If you do not want extensions to connect with programs on your computer, do not install ones that use this permission, or do not install the programs they interoperate with.

And if you like LastPass, ask them to implement profile isolation on Firefox, too. If there is a technical reason that it can only work in Chrome and not Firefox, someone should file a bug to remove the obstacle so there can be feature parity between the browsers.

Here is the fix I came up with that worked... and it was a royal PITA.

deleted all of the four profiles having this problem... and completely started from scratch, again.

It seems to be working now. I have no idea why it didn't/wouldn't before... ????

Zor said

I can't understand why FF would allow ONE extension to bleed over through all profiles instead of entirely isolating it.

And if you like LastPass, ask them to implement profile isolation on Firefox, too. If there is a technical reason that it can only work in Chrome and not Firefox, someone should file a bug to remove the obstacle so there can be feature parity between the browsers.

That WOULD make sense, EXCEPT it did it a few profiles, NOT ALL. So it wasn't the extension itself, unless somehow it selectively applied this bug/problem ONLY to those 4 profiles. The REST of them had NO problem. I just wiped all of the "offending" ones out and recreated them - took a little over an hour to get it all back to "normal"... but that seems to have done the trick. It's weird... lol