Prevent Firefox From Entering Work Offline Mode

Martin Brinkmann
Dec 17, 2010
Updated • Jun 3, 2013

Work Offline is a mode of the Firefox web browser, and the Mozilla Thunderbird email client as well, which prevents the browser from using a computer's or network's Internet connection.

Users can switch to work offline in the file menu of the browser. A click on File > Work Offline changes the mode so that no Internet connections are made by the browser.

A checkmark is placed next to the entry if the Internet browser is set to offline.

Some Firefox users experience problems with the state as the web browser may enter offline mode automatically when it detects no Internet or network connection.

While that works out great most of the time, it can be problematic if your Internet connection is up but Firefox does not detect it properly.

This happens for instance if the computer is connected through a wireless connection, for instance using Wi-Fi on an airport or in a hotel, or even at home or while you are on the road.

Some users are reporting that Firefox starts always offline as their Internet connection is not recognized properly by the web browser on start up.

Firefox 3.6 comes with a new setting that prevents the browser from going offline, ever. The preference does not exist by default and needs to be added to the configuration manually.

Firefox users need to enter about:config in the address bar which opens the configuration listing. The first thing you should do now is enter network.manage-offline-status into the search on top to find out if the preference exists in the browser.

If it is not listed, right-click on the white page on the screen and select New > Boolean from the context menu.

Paste the parameter's name into the preference name field and hit enter. Select false as the value for the preference to disable automatic offline mode in the browser.



If the parameter exists already, make sure it is set to false. You can double-click it to change its value.

The new parameter exists in Firefox 3.6 and all newer versions of the browser. You can still set the browser to enter offline mode manually though by tapping on the Alt-key, and selecting the option under the File menu.

Some users have reported that setting the option to false does not prevent the browser from going into offline mode. First, it is important to note that the browser needs to be restarted before the setting becomes active.

You can modify the following preference in the browser to see if they make a difference:

  • toolkit.networkmanager.disable to true. The manager is used to detect the browser's connection state. If disabled, it is not used anymore to to do. This can fix Firefox always starting in offline mode or switching to the state occasionally.


You can use browser extensions that help you cope with the issue:

  • Offline Restart buttons - Lets you switch between online and offline mode quickly.
  • Work Offline - Similar add-on that adds an offline indicator to the browser UI and provides you with the means to switch between states.

Tutorials & Tips

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  1. david said on June 3, 2013 at 6:50 am

    toolkit.networkmanager.disable does not work too. (restarted firefox)

  2. david said on June 3, 2013 at 4:37 am

    Does not work for everybody: I did it, and when my wifi-router is off it jumps again to offline mode. FF 12.0 in OSX 10.5

    1. Martin Brinkmann said on June 3, 2013 at 5:18 am

      The article has been updates with another about:config preference that you can modify. Please try that and let me know if it resolved your issue.

  3. malti said on August 30, 2012 at 10:48 am

    Its nice…..

  4. malti said on August 30, 2012 at 10:46 am


  5. Anonymous said on April 3, 2012 at 6:07 pm

    Okay, I’ve done this, to no effect. What next? Mac FF 11, no add-ons to cover this, about:config not doing it.

  6. Emmy said on May 9, 2011 at 4:22 am

    THANK YOU SO MUCH! This was the only thing that has worked!

  7. lauryn said on March 10, 2011 at 11:57 pm


  8. vasa1 said on December 26, 2010 at 6:30 am

    Using offline as a filter, I couldn’t find this in about:config in Fx 4 beta 8:

    The closest seems to be this:
    browser.offline (status – user set; type – Boolean; value – false.

    1. Martin said on January 29, 2011 at 6:03 pm

      That’s because you need to create it.

  9. Transcontinental said on December 17, 2010 at 5:01 pm

    Thanks for the information. By the way I wonder how many settings there may be that do not, as this one, exist by default (even if the value is an understandment as here, implicitly, ‘network.manage-offline-status’ is true). I mean, no point in digging in about:config if the setting is not there!

    1. Martin said on December 17, 2010 at 6:09 pm

      I have been pondering about this as well. There surely must be a resource somewhere with all the hidden switches? I have searched and so far have not found it.

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