1964255 - browser.profiles.enabled Your profile cannot be loaded

Status: RESOLVED INVALID

(Toolkit :: Startup and Profile System, defect)

Description

[Samuele Pilleri]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:138.0) Gecko/20100101 Firefox/138.0

Steps to reproduce:

• Enabled browser.profiles.enabled in about:config
• Set up a work profile named "Work"
• Tried to start a session with that profile either using "firefox.exe -P Work" or from about:profiles

Actual results:

Pop-up error saying "Your Firefox profile cannot be loaded. It may be missing or inaccessible."

Expected results:

Firefox launches with the expected profile

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Toolkit::Startup and Profile System' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Joris]

Hello everyone,
I would like to confirm that I have encountered a similar problem on my end and managed to find out more details in regard to its circumstances.
It seems that a new browser profiles functionality introduced in v138 does not work correctly with already existing profiles management tools (in about:profiles).

Problem statement

• A new browser profiles created via new management tool (browser.profiles.enabled) are not displayed in the about:profiles page and they cannot be run with firefox -P $profile-name command.
• Conversely, the new profile management tool does not display any existing profiles created earlier via Create a new profile button in about:profiles page.
• Entries in profiles.ini file for profiles created by new management tool are named inconsistently in comparison to those created by older tool.

Steps to reproduce

1. Run Firefox
2. Browse about:profiles page and ensure that it displays at least two distinctively named browser profiles.
3. Open about:config page and mark the browser.profiles.enabled option as True.
4. Open the profiles menu and observe if there is anything on the list.
5. In the same menu create a new profile named Work.
6. Open about:profiles page and observe which profiles are displayed here.
7. Try to run the firefox -P $profile-name command for all three available profiles.
8. Browse the profiles' root directory and open the profiles.ini file. Observe the entries presented here.

Expected results

• In step nr 4 the new profile management tool should display at least one additional profile.
• In step nr 6 the about:profiles page should display the two already existing profiles and a new one named Work.
• In step nr 7 the command firefox -P Work should open a new browser window with relevant profile.
• In step nr 8 the profiles.ini file should contain three entries titled [Profile0], [Profile1] and [Profile2].

Actual results

• In step nr 4 the new profile management tool displays empty list.
• In step nr 6 the about:profiles page does not display the Work profile, only the two created earlier.
• In step nr 7 the command firefox -P Work fails to open the new window with this profile. Firefox - Choose User Profile dialog window is displayed instead.
• In step nr 8 the profiles.ini file contains two entries [Profile0], [Profile1]. There is no entry for Work profile.

Additional info

Operating System: Fedora Linux 42
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.13.0
Qt Version: 6.9.0
Kernel Version: 6.14.4-300.fc42.x86_64 (64-bit)
Graphics Platform: Wayland

Application Basics:
Name: Firefox
Version: 138.0.1
Build ID: 20250501193411
Distribution ID: fedora
User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:138.0) Gecko/20100101 Firefox/138.0
OS: Linux 6.14.4-300.fc42.x86_64 #1 SMP PREEMPT_DYNAMIC Fri Apr 25 15:43:38 UTC 2025

Comment 3

[Dave Townsend [:mossop]]

The old profile manager and the new profile UI are separate features and not intended to show each others profiles. The -P command line argument only selects profiles from the old profile manager. The described behaviours here are expected.