Open Bug 1476648 Opened Last year Updated 4 months ago

The user can enter online mode without access to the remote config file


(Core :: AutoConfig (Mission Control Desktop), defect, P5)

62 Branch



Tracking Status
firefox62 --- affected
firefox63 --- affected


(Reporter: cbaica, Assigned: mkaply)


(Blocks 1 open bug)



(1 file)

Attached video work offline bug
[Affected versions]:
- Fx 62.0b9
- Fx 63.0a1

[Affected platforms]:
- Windows 10 x64
- Ubuntu 16.04 x64
- macOS 10.14 beta


1.Create a file named autoconfig.js in the location: 
a. "/Applications/" (Mac) 
b. "C:\Program Files\Mozilla Firefox\defaults\pref" (Windows) 
and add the following text to it: 
pref("general.config.filename", "firefox.cfg");
pref("general.config.obscure_value", 0);
pref("general.config.sandbox_enabled", true);

2.Create a file named autoadmin.js on a remote location and add the following text to it: 
lockPref("browser.startup.homepage", "");

3.Create a file named firefox.cfg in the location: 
a. "/Applications/" (Mac)
b. "C:\Program Files\Mozilla Firefox" (Windows)
and add the following text in it:
lockPref("autoadmin.failover_to_cached", false);

[Steps to reproduce]:
1. Launch Firefox (with a fresh profile).
2. Open a new tab and try to navigate to a website (e.g.
3. In the displayed page, click the 'Try Again' button.

[Expected result]:
- The user should be kept in 'Offline mode' and the website shouldn't load.

[Actual result]:
- The website is loaded, even though the user does not have access to the remote config file, the "Work Offline" is no longer checked but it is still grayed out.

- Restarting Firefox by closing and opening it again will launch it again in "Offline mode".
Priority: -- → P5
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