Noticed that Firefox was opening with the wrong profile after creating a new profile in about:profiles.

Steps to reproduce:

1. Delete ~/.mozilla/firefox
2. Download and install Firefox 67
3. Start Firefox
4. Quit Firefox
5. Open Firefox
6. Create a new profile named "whatever"
7. Quit
8. Start Firefox

What happens:

Firefox starts up in profile named "whatever"

Expected result:

Firefox should open in default profile, like it did in Firefox 66.

Contents of profile files after step 4:

installs.ini

[8050D45F76B92B26]
Default=qzxuo9ys.default-nightly
Locked=1

profiles.ini

[Profile1]
Name=default
IsRelative=1
Path=en77g6hs.default
Default=1

[Install8050D45F76B92B26]
Default=qzxuo9ys.default-nightly
Locked=1

[Profile0]
Name=default-nightly
IsRelative=1
Path=qzxuo9ys.default-nightly

[General]
StartWithLastProfile=1
Version=2

Contents of profile files after step 7:

installs.ini

[8050D45F76B92B26]
Default=xpkbk27j.whatever
Locked=1

profiles.ini

[Install8050D45F76B92B26]
Default=xpkbk27j.whatever
Locked=1

[Profile1]
Name=default
IsRelative=1
Path=en77g6hs.default
Default=1

[Profile0]
Name=default-nightly
IsRelative=1
Path=qzxuo9ys.default-nightly

[General]
StartWithLastProfile=1
Version=2

[Profile2]
Name=whatever
IsRelative=1
Path=xpkbk27j.whatever

How are you creating the new profile?

I am navigating to about:profiles, clicking "Create a New Profile", clicking next, typing a name, and clicking "finish".

Looks like this was introduced by bug 1322797. We no set the newly created profile to be the default. Not really sure if that is right or wrong.

Given that my the profile I originally launched with does not have a "Set as default profile" button alongside it, I think it is clearly a bug - not only that, it is a regression of previous behavior.

(In reply to Asif Youssuff from comment #5)

Given that my the profile I originally launched with does not have a "Set as default profile" button alongside it, I think it is clearly a bug - not only that, it is a regression of previous behavior.

That's odd, it does for me.

(In reply to Dave Townsend [:mossop] (he/him) from comment #6)

That's odd, it does for me.

I am now seeing the same thing, but I didn't see it when I reported using the older build.

This continues to be annoying; if I create a new profile for testing, the new profile is immediately set as my default profile, even when I had a default set previously.

If I forget to set my default profile back to my original default, I end up starting a test profile without any interesting stuff in it the next time I update Nightly.

Reproduced on MacOS 10.15 and M1, marking affected flags accordingly.

Reproduced on Ubuntu 20.04 as well.

This behaviour is known and will affect all versions on all platforms, there is no need to confirm that.

Any workaround suggestion in the meantime, please?

Example of the impact of this bug:

Not able to log anymore into Postman (desktop and web application)
because a new Firefox profile (configured with strict privacy settings)
is launched without being the default one,
hence the ineffective login.

(In reply to solid.tester from comment #12)

Any workaround suggestion in the meantime, please?

Go into about:profiles and find your profile, then click the "set as default profile", which shall set the selected profile as default for the target install.

(In reply to Dave Townsend [:mossop] from comment #4)

Looks like this was introduced by bug 1322797. We no set the newly created profile to be the default. Not really sure if that is right or wrong.

I'm not a profile expert, but it does seem wrong to me. I thought the last used profile became the default.

Has anyone tested past behavior is for a newly created profile to become the default? Pre bug 1322797? Also, does this also happen when when a profile is created in the standalone profile manager?