Firefox Quantum and CCK2

Folks are asking me about Firefox Quantum and CCK2. Here are the answers to the most common questions.

The CCK2 Wizard is not working on Firefox Quantum. When are you going to update it?

The CCK2 Wizard is a legacy extension and as such will not work beyond Firefox 56. In order to use it, you’ll need to keep a copy of the Firefox 52 ESR around. The CCK2 Wizard does lots of interesting things (reading prefs, reading search engines, reading files, writing files, etc.) that are not possible in a WebExtension. Because the wizard itself is something that is used rarely (only to setup or modify a configuration), I don’t foresee a problem with this decision.

My CCK2 configuration is not working on Firefox Quantum. I get the message “Failed to read the configuration file. Please contact your system administrator.”

I updated the CCK2 Wizard to support Firefox Quantum on October 12. Those changes require that you push out an update to the CCK2 to your clients. The only files that need to be updated are the files in the cck2/modules directory. I recommend pushing out an update to cck2.cfg as well because I record the version of the CCK2 Wizard used to generate the config in that file. This makes it easier to debug things.

Going forward, when I update the CCK2 Wizard, I will display a web page letting folks know that they need to update their client configurations. I will also put on the CCK2 Wizard’s main page.

Can I still generate an extension with the CCK2 Wizard?

Starting with Firefox Quantum, AutoConfig is the only mechanism that will work with Firefox since the CCK2 Wizard generates legacy extensions. I have been recommending AutoConfig as the preferred method for a while now. I do not plan to remove the ability to create an extension, but I will be putting a warning around it.

Are you going to continue to update the CCK2?

Yes. I will continue to update the CCK2 for the foreseeable future. There are a few small issues with Firefox Quantum that were found as well as issues with Firefox 58. I plan to release an update to address these in the next week.

Where do I report problems with CCK2?

If you are simply reporting bugs, use Github. If you have a general question or have paid support, you can use Freshdesk.

Please note: I reserve the right to delete comments that are offensive or off-topic.

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36 thoughts on “Firefox Quantum and CCK2

  1. I installed today a fresh version of CCK2 ( under Firefox 52 ESR, imported old config from 2016-12, exported AutoConfig.
    After applying to Firefox 57 (which can not start because error with configuration file) –> Problem with configuration file exists furthermore. 🙁
    How can we solve this problem? The important workplaces are downgraded now to FF 52 ESR, but we have some workplaces which need the newest FF 57 + (e.g. for software test).

    • I am still trying to determine the source of this problem.

      I have been given failing configurations to test, but they work on my machine, so it appears to be something in the profile.

      I am continuing to investigate.

      Would you be willing to send me your configuration to see if it recreates the problem locally? If so, please use

      • Once you replace the files, you often have to start FF in Safe Mode once in order to clear the error.

        Just start in Safe Mode (Shift double click).
        Close Firefox.
        After that is should open fine.

        This doesn’t happen in every case, but I’ve seen it in a fair number of my devices.

  2. Hi,
    not everyone of my users has to use the firefox addons Clippings and greasemonkey. Up until now I used to install them just by copying them into C:\Program Files (x86)\Firefox\cck2\bundles. But greasemonkey 4.0 and clippings 6.0 won’t load. I’m using Firefox 57.0 64 bit. Is there anything I can do, to start these addons without actually installing them to user profiles?


    • Because they are web extensions now, you can’t use the bundles mechanism. So you will have to explicitly install them to the profile using the CCK2 or some other method.

  3. Sorry for intruding as I am not a deveeloper or professional, but an ordinary
    amateur. I have just downloaded the new Firefox browser and get an error message
    every time I open the browser. I certainly do not have CCK2 installed although
    there may be some residues from a previous user.I would like to send you a screen shot which should make things clear. Can I do this? Best wishes to you all Reg Truckle

    • Hello Reginald,

      Though this is certainly not the best place to come for general support for the Firefox Browser (Mozilla’s Community Support facilities would be a good place for that –, I’ll do my best to assist you.

      My first recommendation being a new installation of the browser for you would be to launch Firefox whilst holding down the “Shift” key on your keyboard – this will present options to reset Firefox or to launch it in safe mode.

      Try launching the browser in safe mode once, then after that close out of it and launch it normally to see if the issue is resolved.

      You may need to choose the option to reset Firefox if safe mode does not work.

      Have a great day!

      • Hi pitcherj, Thank you for your help. I opened Firefox in safe mode,closed it again , and opened it normally and it worked. The message did not re-appear. Thank you again,and thanks to all who responded, problem solved.
        Best wishes RegT

      • Hi Mike, Thank you and all yhe team for such a generous response to an ordinary user and not a professional.
        I opened a ticket as you suggested and sent the screenshot for your info.The ticket number was 1847759. The problem of the error message was solved by “pitcherj”
        (see above). My best wishes and thanks to you all. RegT

  4. I belive the simpliest method would be to create a small standalone application (wizard) and not an extension anymore. The program than has the option to export the config files that needs to be copied to the firefox program folder.

    As far as I can see with FF57 the AutoConfig still works, the problem is only with the extension, so why not solving it with an external standalone application?

    • Or maybe ‘port’ the wizard part to a web app e.g. using something like PHP on
      a web server to create and package up CCK2 AutoConfig files ? – which could be made available over the Internet for anyone to use, or to download and install on an internal web server?

  5. Hi Mike:

    I just want to say thank your hard work on CCK2 and for making it accessible to the general public. I’ve learned so much from your sources and with the help of CCK2 I am able to restrict extension addons.

    Thanks again.

  6. I use the latest CCK2 with Firefox 56.0.2 to generate a template. I then use autoconfig and install the settings in to the new Firefox 57. Most settings works fine so we are happy. Thank you for an awesome product Mike.

  7. I receive errors launching Firefox 58.0b9 connected to cck2.cfg. I add the referenced code lines at the right within curly braces:

    [Exception… “Component returned failure code: 0x80004002 (NS_NOINTERFACE)
    [nsIPrefBranch.setComplexValue]” nsresult: 0x80004002 (NS_NOINTERFACE)” location:
    “JS frame :: resource://cck2/Preferences.jsm:: _set :: line 194” data: no]

    _set@resource://cck2/Preferences.jsm:194:11 {this._prefSvc.setComplexValue(prefName, Ci.nsISupportsString, string);}
    set@resource://cck2/Preferences.jsm:152:5 {this._set(prefName, prefValue);}
    init@resource://cck2/CCK2.jsm:170:7 {Preferences.set(“extensions.cck2.” + + “.installedVersion”, config.version);}
    @cck2.cfg:668:1 {Components.utils.import(“resource://cck2/CCK2.jsm”);}

    Do you plan to fix these errors bevor the release of 58.0?

    Thanks a lot.

      • I downloaded the latest cck2wizard ( today and I’m still getting a very similar error to Klaus on a machine:

        [Exception… “Component returned failure code: 0x80004002 (NS_NOINTERFACE)
        [ns|PrefBranch.setComplexValue]” nsresult: “0x80004002 (NS_NOINTERFACE)” location: “JS frame :: resource://cck2/Preferences.jsm :: _set __ line 194” data: no]


        We don’t have a lot of Quantum users in my company yet, most are on the ESR branch. I use Developer Edition and I have not gotten this error, but one of my only Quantum users has gotten it.

        How can I fix it? How would you like me to send any additional information, and what additional info would you like?

        Thank you!

        • Looks like your Quantum users are still using an older release of cck2

          You need to replace all the files in the cck2/modules directory/folder with the matching files from the download

          • I can confirm this error. It happened after Firefox upgraded to 58 and there was already profile that was created with Upgrading to did not resolve existing profiles, but new profiles were fine.

            On existing profiles, I found that deleting startupCache\scriptCache-current.bin resolved the problem. I’m not sure how safe deleting that file is, but I found no easy way to have firefox force a rebuild.

            • The way I have been updating the autoconfig is by deleting the cck2\modules folder and re-expanding the autoconfig. And it seemed I could do it without inconveniencing my users because it appeared that I could do it while Firefox was running and the next time it launched it’d use the new config.

              Not so. I got it to work by shutting down Firefox first, deleting the entire cck2\ folder, then re-expanding the autoconfig file into the directory. That time I didn’t get the error.

              Granted, so far this is with the one user that reported the problem and we might have 4 Quantum users in the whole company so far, so not a whole lot of data points from me yet.

              • I think I understand. But I suspect you would need to start Firefox with the CCK2 removed, before re-expanding the autoconfig file. So:

                Shutdown Firefox
                Remove Old (any) CCK2 files
                Start Firefox (and perhaps Shutdown Firefox)
                Re-expand CCK2
                Problem solved???

                Perhaps that flushed the startupCache\*.* files. I’ve decided to just delete the entire folder from all the profiles (removing just scriptCache-current.bin did not fix the problem in all cases) because I can do this from a GPO and fix all users without needing to start or restart Firefox.

              • You are correct in that most of the time replacing the files in cck2/modules is enough to upgrade the CCK2. Unless you made change to your config, none of the other files are important.

          • The problem is that it says that Firefox 58 says that CCK2 is not compatible with the browser.

            I receive the same error during startup that Len has.

            • The CCK2 extension (aka the ‘CCK2 wizard’) is not compatible with Firefox 57 and 58 – but the resulting cck2.cfg file and cck/modules files when generated by the latest CCK2 extension using an older version of Firefox will work with Firefox 57 and 58.

              See the start of this blog post for more details

  8. My CCK-Autoconfig has a problem. Addons that are installed via CCK will be installed when Firefox is first started and will be removed if their addon-id consists of numbers.

    Adblock Origin for example will not be removed (addonid

    But Greasemonkey and Clippings will be removed at the second start. (Ids {91aa5abe-9de4-4347-b7b5-322c38dd9271} and {e4a8a97b-f2ed-450b-b12d-ee082ba24781})

    Do you have any idea why this could happen? If I remove CCK after the first start, these addons remain in the profile.

  9. After updating to firefox 58 and cck2, I have found that adding a site that allows popups on the permissions tab, causes a crash in firefox when running it for the first time when it is creating the profile.

    • I see the same issue with Firefox 58 – although not with Firefox 59.0b4 or 60.0a1 (nightly) – so I guess whatever broke in 58 has already been fixed in later versions?

  10. Hello Mike,

    I just noticed that Firefox is goint to implement a new way to define perconfigured settings via .json File that will be part of FF 60 ESR:

    Will this be the end of CCK2 or are you planing to make a tool to be compatible with that?

    I really like Firefox but a the moment it is a real pain using it with the cumbersome way to preconfigure it with CCK2 in non-ESR versions.
    FF 60 ESR is planned for May 2018 and at the moment I really tend to switch to Chrome with legit GPO although I would love to keep Firefox due to privacy reasons.

    Maybe you could give us a short roadmap of CCK2!

      • Hello Mike,

        thank you for your statement. That sounds good!
        Do you know if GPO / Policy Engine will only work for ESR versions or for regular versions, too?

  11. I think my question in all of this is – why does CCK2 keep breaking with new releases of Firefox and/or why does CCK2 need to keep changing to prevent these error messages from appearing when a user upgrades their browser?

    Is there a way to prevent the error message from appearing at launch, or at bare minimum give an option for it to fail silently rather than inundate the help desk with phone calls of users with a cryptic error message when their browser updates?

    Will a future version of CCK2 make the product less susceptible to browser updates breaking functionality?

    • I agree with Jacob, if there was a way to make the silence the error message (since the error doesn’t seem to affect FF) that would be really useful.

  12. I’m somewhat new to CCK2. Is there any dormal documentation? I used bits a pieces of previous post but I’m having issue getting CCK2 to work with Firefox 52.6.esr. The CCK2 add-on is disabled because it considered a legacy extension and maybe I’m missing a step. Any help would be awesome.