Linux Solutions: Why does Firefox start in offline mode?

Jack Wallen
Apr 20, 2009
Updated • Dec 28, 2012

If you have this problem you know how frustrating it can be. Every time you fire up Firefox it wants to start in offline mode. To get around this you have to go to the File menu and uncheck the Work Offline box.

When I first encountered this I immediately opened up about:config and searched everywhere for the entry that was causing this issue. No luck. Every possible entry "" entry was checked as "true", but still the browser would start offline. Everywhere I looked it seemed it was set up properly...and this shouldn't be a difficult issue. It was turning into a hair-losing situation. Eventually, however, I would figure out what was going on.

In many modern Linux distributions network management is controlled by the user-friendly NetworkManager utility. Sometimes there is a bit of a disconnect between Firefox and NetworkManager.? This doesn't happen often (Most often this happens in Fedora.), but when it does happen it will make you feel like you have no idea what you are doing.

There are two ways to get around this. The first way is go hop on to Firefox, open the about:config window (you will most likely have to click the check box promising you'll be careful using this configuration page), and do a search for the string:


By default this is set to false which means it is working in conjunction with NetworkManager to see if there is a connection. Set this string to true, restart Firefox, and you most likely will not have this problem again.

Figure 1
Figure 1

If you'd rather not monkey with the about: config page in Firefox you will have to change a setting in NetworkManager itself. You will find the NetworkManager entry in the Administration sub menu of the System menu. The entry is labeled "Network". Click on the Network entry to open up the NetworkManager window (see Figure 1).

Select your method of connecting to the net and click the Edit button. A new window will appear that allows you to edit various aspects of this connection.

Figure 2
Figure 2

There is only one configuration you need to change here. If the box next to "Controlled by NetworkManager"is checked, uncheck it. If it is unchecked, check it. This will depend completely on how you manage your network connection.

Firefox by default uses NetworkManager to know if a connection has been made. If you use another tool for your network connection, and you have Firefox enabled to check NetworkManager, you will always start off line, because Firefox will think you have no connection.

My suggestion is that you first try the about:config entry. If that doesn't work then give the NetworkManager approach a try. One way or another, you will be able to stop this insipid behavior.

Final Thoughts

The real culprit here, in my opinion, is that the developers of NetworkManager and the developers of Firefox can't seem to agree on a standard. This, of course, is a problem that haunts Linux in a number of areas. In the case of this one issue, you now know a way around it.


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  1. Franco said on August 20, 2011 at 2:42 pm

    It worked! Thank you man. Thank you a lot.

  2. Ian said on July 21, 2011 at 11:23 am

    Thanks, Jack.

    On Firefox 3.6.18 on Ubuntu 10.04:


    did the trick for me.

  3. bruce said on July 12, 2011 at 2:51 am

    thanks for answer and for hosting answer

  4. ada said on February 22, 2011 at 6:28 am

    i lost my search box.. and my firefox went offline mode. is that going to be forever?

  5. xfrabbit said on November 12, 2010 at 3:12 am

    belated thanks. this started happening to me after i switched to wicd instead of using network manager. all better now!

  6. Android Incredible said on July 15, 2010 at 7:37 pm

    Typo in search string: toolkit.networkmanager.disble

    Should be: toolkit.networkmanager.disable

  7. Bunny said on November 10, 2009 at 8:47 pm

    Interesting. When I try that, I can’t find any string that contains “toolkit” (or even “tool”)

    I’m using Firefox 3.0 — Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9) Gecko/2008061015 Firefox/3.0

    Can’t find “network” in there either!

  8. Bunny said on November 10, 2009 at 7:56 pm

    I have no idea what you mean when you say you “opened up about:config.” Can you please explain?

    1. Martin said on November 10, 2009 at 8:19 pm

      Bunny it means to enter about:config into the address bar of Firefox.

  9. a said on November 7, 2009 at 1:22 am

    thanks, solved my problem

  10. Ritesh said on November 4, 2009 at 8:01 am

    thanks a lot , it solved my problem

  11. Colin said on June 21, 2009 at 4:32 am


  12. Bob Shaw said on May 26, 2009 at 4:52 pm

    My Firefox has begun going INTO offline mode after it’s been running for a while. Any thoughts on a) why, and b) how to fix it? Thanks!

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