1908590 - Firefox autostarts in the background even when disabled in settings

Status: RESOLVED INVALID

(Firefox :: Shell Integration, defect)

Description

[sworddragon2]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:128.0) Gecko/20100101 Firefox/128.0

Steps to reproduce:

1. Install Firefox without the Mozilla Maintenance Service (if this is still a thing today).
2. In about:preferences#general make sure the checkbox to open Firefox automatically is disabled.
3. Check your taskmanager (or alternatively system settings) that no autostart entry for Firefox is present/enabled.
4. Check that no services for Firefox exist/autostart (e.g. via msconfig and filtering for non-Microsoft services and/or checking that services.msc has no Firefox/Mozilla services).

Actual results:

On a reboot (first 1-2 minutes) I noticed that at least 2 Firefox processes were running in the background for a short amount of time until they vanished.

Expected results:

No autostart of Firefox should have happened (imagine every installed application silently autostarts now in secret - that would be a very significant boot delay on HDD's (and possibly SSD's)).

Additional details:

I'm actually wondering if this is related to the recent autostart setting in about:preferences#general and if that autostart actually checks for the user preference to open the browser in the foreground then. But if this guess is true I'm wondering why Firefox does not utilize the operating systems (here Windows 10) mechanism for doing this. Maybe it would require an elevated prompt on toggling the setting in about:preferences#general then? But even then it should not be an issue. At least Firefox should not try that hard to hide its (non-deactivateable?) autostart. Unless this theory is false, then just ignore it.

Comment 1

[Nipun Shukla]

Hi there, thanks for the report! On an implementation level we do use the Windows mechanism to launch on startup and there shouldn't be any way (related to this feature at least) for Firefox to silently launch and close shortly after. Just in case, can you verify that no keys pointing to your Firefox executable exist at HKCU\Software\Microsoft\Windows\CurrentVersion\Run and that no shortcuts exist at %USERNAME%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup?

My first guess is that this is some kind of background task. Can you double check in Task Scheduler and make sure there are no scheduled tasks in the Mozilla folder?

Comment 2

[sworddragon2]

(In reply to Nipun Shukla from comment #1)

Just in case, can you verify that no keys pointing to your Firefox executable exist at HKCU\Software\Microsoft\Windows\CurrentVersion\Run

Only the Standard entry and an entry for GOG Galaxy exist there - so nothing related to Firefox.

(In reply to Nipun Shukla from comment #1)

and that no shortcuts exist at %USERNAME%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup?

This folder is empty (besides the hidden desktop.ini).

My first guess is that this is some kind of background task. Can you double check in Task Scheduler and make sure there are no scheduled tasks in the Mozilla folder?

In the Mozilla folder is the task "Firefox Default Browser Agent some_random_characters". It claims to start every day at 13:06 and wants to run next in about an hour. But it also claims it did never run so far with the code 0x41303.

Now I remember something: I think the event log showed some errors in the past related to this and there is a bug report about it.
Edit: I just checked it and there is indeed an entry in the event log (and it is currently the only one for it) dated at 29th december 2023 which shows an error for "Firefox Default Browser Agent" with the event ID 2 and I think it is the same as bug #1834188 .

So, did I just see this task running by random early at the booting process and thus was thinking there was some autostart? I guess all might be fine then unless that behavior is not normal or the code 0x41303 implies some strange error.

Comment 3

[sworddragon2]

(In reply to sworddragon2 from comment #2)

Edit: I just checked it and there is indeed an entry in the event log (and it is currently the only one for it) dated at 29th december 2023 which shows an error for "Firefox Default Browser Agent" with the event ID 2 and I think it is the same as bug #1834188 .

My bad, it actually still shows quite a lot of entries (I thought older ones might have been cleaned up). The most recent one is dated at February 20th, 2024.

Comment 4

[sworddragon2]

Edit: I also just saw in the task scheduler that Firefox Default Browser Agent did sucessfully run and the code is 0x0 so I guess this seems to be fine then as well.

Comment 5

[Nipun Shukla]

In my estimation it seems pretty likely that what you saw was the WDBA scheduled task. Given that, it looks like everything's been resolved so I'm going to close this bug. Feel free to open it again if anything comes up.