Firefox 49: two new system add-ons to fix Flash and graphics issues

Martin Brinkmann
Oct 20, 2016

Mozilla has started to distribute two new system add-ons for Firefox 49.0 and Firefox 49.0.1 to address two issues affecting Adobe Flash Player and graphics issues.

The organization is working on Firefox 49.0.2 currently, but made the decision to release two new patches for the current stable version of Firefox as system add-ons to address issues that users are affected by.

System add-ons are like hotfixes. They can be pushed out to all Firefox users who have automatic updates enabled to fix issues of the browser. That's usually a lot faster than having to create a new build of Firefox.

The two system add-ons address two issues in Firefox 49 and 50.

Asynchronous Plugin Rendering and D3D9 Acceleration Fallback

firefox 49 system addons

Asynchronous Plugin Rendering enables asynchronoous plugin rendering in Firefox 49. The patch is designed to improve the performance of Adobe's Flash Player in Firefox, and to reduce the likelihood of crashes.

The patch flips the switch dom.ipc.plugins.asyncdrawing.enabled to true on Firefox 49 and Firefox 49.0.1. This fixes an issue that 64-bit users of Firefox experienced. Mozilla calls these issues "functional", and mentioned that it also caused issues with scrolling for e10s users and Flash content.

Mozilla will integrate the change in Firefox 49.0.2 which will be out soon. If you don't want to wait for the system add-on to be pushed to your copy of Firefox, flip the preference manually instead to resolve the issues:

  1. Type about:config in the Firefox address bar.
  2. Confirm that you will be careful if the warning prompt spawns.
  3. Search for dom.ipc.plugins.asyncdrawing.enabled.
  4. If the preference's value is set to false, double-click it to set it to true instead. This enables asynchronous plugin rendering in Firefox.

The D3D9 Acceleration Fallback system add-on on the other hand deactivates Direct3D9 fallback if hardware acceleration is enabled in Firefox. This should fix graphics artifacts issues that some Firefox users are experiencing currently. The patch will land in Firefox 49 and Firefox 50.

Find out if the system add-ons are installed

You can find out if the system add-ons are already installed on your version of Firefox. Simply load about:support in the Firefox address bar and scroll down to the extensions group on the page.

There you find all user installed and Mozilla installed Firefox add-ons. If you find the two system add-ons mentioned above, then they are installed and enabled. If not, there is little that you can do but wait for them to become available on your system. (via Sören Hentzschel)

Firefox 49: two new system add-ons to fix Flash and graphics issues
Article Name
Firefox 49: two new system add-ons to fix Flash and graphics issues
Mozilla has started to distribute two new system add-ons for Firefox 49.0 and Firefox 49.0.1 to address two issues affecting Adobe Flash Player and graphics issues.
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  1. AW said on April 14, 2017 at 6:58 am

    Thank you very much!

    I was having blank/black screen on some websites flash videos whenever I would scroll my mouse over it. Enabling or disabling hardware acceleration, as suggested by some websites, did nothing. But your suggestion on changing “dom.ipc.plugins.asyncdrawing.enabled” to true solved the issue.

  2. Michel C said on December 16, 2016 at 2:34 pm

    I upgraded Firefox from 49 to 50, 50.0.1, 50.0.2 and just updated to the new 50.1.0. This is with Korora 24 Linux, which I’ve been using for well over a month now and will soon upgrade to Korora 25. Checking about:support, I think this article by Martin isn’t for Firefox on Linux.

  3. Michel C said on October 28, 2016 at 7:19 pm

    What is “asynchronoous plugin rendering“? Also, what is e10?

    I have, while not of my choosing, 32-bit Win 7 and Firefox 49.0.2. dom.ipc.plugins.asyncdrawing.enabled is set to true, but checking installed extensions, I don’t see any that appear to be of the ones your article is about but there’re three that weren’t installed by me; the extensions Pocket, WebCompat and Firefox Hotfix 20160826.01.

    I don’t have a clue what those do and could do a Web search to find out, but whatever they’re for, they’re not helping with the problem of tab windows suddenly becoming fully, sometimes partially but often fully, blacked out, causing loaded Web pages to become lost in pitch black darkness. Reloading the pages sometimes helps to correct this problem but this often fails, including when reloading pages while pressing the Shift key for (I think) a full or clean refresh of the page. I then terminate and restart Firefox, but the blackening problem soon re-occurs.

    That’s for tab windows and not the full laptop monitor or screen. The blackening is only within tabs and often is, at first anyway, for the full tab window, while reloading a page can produce one that isn’t completely black, though much of it is still black. When this happens and I switch to a different tab that has a Web page loaded in it, it’s also blacked out.

    This problem doesn’t occur with the Opera browser and I also have Google Chrome installed though haven’t used it enough to be able to know if it’ll black out or not.

    1. Michel C said on October 28, 2016 at 7:58 pm

      Actually, just noticed another Firefox extension I didn’t personnally install and it’s “Multi-process staged rollout”.

    2. Tom Hawack said on October 28, 2016 at 7:54 pm

      In fact the modified ‘Asynchronous Plugin Rendering’ and the ‘D3D9 Acceleration Fallback’ are described as system add-ons because if the WebCompat system add-on is running then this system add-on will have authorized (downloaded) the two mentioned modifications :

      // Enable Asynchronous Plugin Rendering
      user_pref(“dom.ipc.plugins.asyncdrawing.enabled”, true); // default was false before 49.0.2
      // Enable D3D9 Acceleration Fallback : NO (OK)
      // user_pref(“layers.allow-d3d9-fallback”, false); // default was true before 49.0.2

      Users who have not allowed the WebCompat system add-on to run (either by deleting it from Firefox’s install folder / browser / features sub-folder or by disabling it with the CCleaner application), had two possibilities :
      1- Change manually the above settings in about:config
      2- Wait for Firefox 49.0.2 which included these modifications along with security fixes.

      This is why you have dom.ipc.plugins.asyncdrawing.enabled set to true : it’s been done automatically.
      From there on it appears that this setting is problematic for many users of Flash, hence it is advised to revert dom.ipc.plugins.asyncdrawing.enabled to false, as it was before.

      A bit complicated, I agree, even if easy when we don’t try to understand.

      Concerning e10 Electrolysis, it’s a topic by itself and I won’t expose my lack of in-depth knowledge to approximations. But here on gHacks you’ll find several articles and several Mozilla wikis explain the matter.

      1. Tom Hawack said on October 29, 2016 at 1:17 pm

        @ Michel C

        Je vous ai répondu mais apparemment mon commentaire tarde à être publié; cela arrive parfois.

        Vous citez Firefox, ” “Désactivé par des modules complémentaires”. Si vous le désirez appelez-moi en résolvant l’énigme de mes départements préférés ci-après affichés et je pourrais peut-être vous aider de vive voix. La France est belle et j’affectionne en particulier l’Aisne, le Lot-et-Garonne, l’Eure-et-Loir, le Tarn, la Haute-Vienne

        A bon lecteur, salut!

      2. Tom Hawack said on October 29, 2016 at 11:09 am

        @Michel C,

        You write, “could e10 being set to false be the cause of the blackening problem I’m frequently having?”
        No, absolutely not. e10 set at false is normal, it still is the default value and it is handled by the [email protected] system add-on. e10 is being rolled out progressively only. Users will not have problems with e10 disabled, but they may encounter problems related to non-e10 compatible add-ons when e10 is or will be enabled on their Firefox.

        For your video problem, if it concerns Flash videos, I suggest you set :
        dom.ipc.plugins.asyncdrawing.enabled to false in about:config

        If you wish to know which of your installed FF add-ons are e10 compatible or not, you may have a look in the following file located in your FF profile folder : extensions.ini — There is a section in that file called [MultiprocessIncompatibleExtensions] which lists the e10-incompatible add-ons you are running. But I repeat : this cannot have anything to do with your video problems since e10 is at this time — as you write it — not enabled for your installed Firefox.

        As I read you it seems the specific Firefox video rendering issue integrates in a wider system-wide problematic. The cause therefor could be elsewhere than in Firefox itself.

        Remember that sometimes uninstalling and re-installing an application, a browser: Firefox, can fix issues.
        I’m afraid at this time and with the little I know of your Firefox / OS configuration I won’t be able to be of much more help. If you have a specific — square, narrow — question, maybe I or someone else here will be able to answer.

      3. Michel C said on October 28, 2016 at 9:20 pm


        Thanks for the very, very prompt reply. Re. Asynchronous Plugin Rendering, about:config shows that this option or feature is set to true and that D3D9 … is set to false. about:support shows that e10 is set to false due to “Désactivé par des modules complémentaires”, so due to de-activation because of some complementary modules, by which I guess is meacnt extensions and/or plugins. Which ones is unfortunately not specified, but could e10 being set to false be the cause of the blackening problem I’m frequently having?

        A Web search for e10 produced the following link.

        “Multi-Process Firefox: everything you need to know
        By Martin Brinkmann on July 22, 2016 in Firefox – Last Update:July 22, 2016”,

        Unfortunately, about:support doesn’t indicate which add-ons or plugins are causing e10 to be disabled and I’d like to try as the GHacks article says can be tried, which is to force-enable e10, but I don’t know how to back up my Firefox profile, not knowing where the personal Firefox folder is located. With XP, we just needed to go to the (if not mistaken in the name) Applications subfolder of a user account, but I don’t find anything like this with Win 7 so am left wondering where to look.

        If it all goes well, then I’ll have Korora 24 Linux installed for a dual-boot system with this laptop by Sunday and will then cease using Windows from MS, except occasional use. This will hopefully put an end to the blackening problem as well as Firefox crashing and, sometimes, the whole system, Win 7, apparently freezing up such that the mouse doesn’t work and pressing keys, f.e., CTRL-ALT-DEL to try to reboot, also not working. Using Linux will hopefully put an end to these “extraordinary” problems.

        I say “extraordinary” due to never having experienced these problems prior to receiving this Dell Latitude E6500 laptop with 32-bit Win 7 already installed; in France French with a keyboard that doesn’t show any French characters on the keys, so I guess an English language keyboard. I’ve used Windows since Jan. 1995, Win 95, 2000 and XP, plus also used, for some school courses, Win 7 Pro, and though I occasionally needed to use the Win 2000 installation CD to do some repairs to Win 2k installations, the process always worked. This black-out problem currently experienced is novel to me.

        It doesn’t always happen though. Maybe it’s only when I’ve loaded some video pages, for right now, I’ve been using Firefox for a couple of hours and the black-out problem hasn’t happened during this session, during which I haven’t gone to any video pages.

        If it does happen only after going to video pages, then I guess that the problem is with graphics; but, the problem doesn’t occur with Opera. With videos, at Youtube and anyway, and when using Firefox, I often get video loading error messages instead of the videos, and when I get the visual part of videos at Youtube, there’s no audio. So, I copy the url and use it with Opera, which doesn’t fail. It doesn’t fail to correctly play the video though does fail for login. For some reason I’m not sure about, Google isn’t letting me log in using Opera for my Youtube account, but Opera otherwise does work for playing the videos.

        I’d like to download the .iso for creating a Win 7 installation CD/DVD from Microsoft, which provides this option on the surface; saying on the surface because we get the page with the download links, but they don’t work, even after years of people posting about this problem. If I could get the free installation download, then I’d do a full re-installation of Win 7, this time in English for better compatibility with the laptop’s keyboard, but the download links aren’t working for me and many people have reported, posted about having this problem for several years, according to my Web searches anyway.

        Before this laptop, obtained in Sept. 2016 through an aunt, I always used towers or mini-towers and never had similar problems with those. Laptops are evidently also lousy because of the keyboard. Often, as I’m writing, the cursor disappears into wherever it goes for I no longer see it and need to re-click in an edit or comment box to bring the cursor back; another novelty for me.

    3. Michel C said on October 28, 2016 at 7:32 pm

      Timer timed out, so I’m adding a second post.

      I tried Web searches a few different times about this black-out problem with Firefox but haven’t succeeded in finding a solution. Doing the search using firefox and black for search terms produces plenty of links, but not for pages created in 2016 and of those I read, none seem to be about the blackening problem I’ve been having with 32-bit Windows 7, current or up-to-date Firefox, and this Dell e6500 laptop an aunt obtained for me last month, Sept. 2016.

      The graphics driver is from NVIDIA and the CPU is Intel. NVIDIA apparently became, before I received the laptop, screwed up, for when checking out nView, which is installed with the nvidia driver, an error was reported, saying that there was an incompatibility problem. So I checked at the nvidia website to see if it’s possible to download the driver installer, to do a fresh reinstallation. An update is offered, so I downloaded and installed it; but, this hasn’t helped with the blackening problem when using current Firefox.


      1. chris parke said on May 1, 2017 at 1:26 am

        I have this problem as well, complete loss of the web page graphics and a black screen within the browser window. All sites are the same once the first page is blackened. Restarting the browser normally fixes the problem but one time did not until I went away on another bowser and later reloaded FF. I use Windows 10 with the Creators Update and FF 53.0
        The problem arose after that update. The crash results in a .dmp file which points to the Nvidia driver failing to refresh . I sent the dump to Firefox and Nvidia . The black screens do not appear related to flash videos and are intermittent and unreproduceable but frequent enough to need attention.

  4. Larry Wickham said on October 24, 2016 at 6:37 pm

    After 49.0.2, ALL videos on would play the ads preceding videos correctly; but, when it switched to the videos, the screen would turn white. I could hear the audio, but not see the video. Going into about:config and toggling the dom.ipc.plugins.asyncdrawing.enabled from true to false fixed the problem. I got a callback from Mozilla that I requested, but when I told the tech about this, and attempted to discuss it, he hung up on me!!

    1. Larry Wickham said on October 24, 2016 at 9:51 pm

      I just got off the phone with Firefox support?, and they said the problem is with Flash Player – a compatibility issue that only Adobe can fix!!

  5. bjm said on October 22, 2016 at 4:11 pm

    Q:) are two new system add-ons to fix Flash and graphics issues found with Firefox x64.
    I’m not finding Asynchronous Plugin Rendering and Composting is Basic with my FF49.0.2 x64.

    1. Tom Hawack said on October 22, 2016 at 4:22 pm

      No new system add-ons, the issues have been fixed by replacing default settings :
      EnableAsynchronous Plugin Rendering : dom.ipc.plugins.asyncdrawing.enabled : false->true
      Remove D3D9 Acceleration Fallback : layers.allow-d3d9-fallback : true->false

      1. bjm said on October 25, 2016 at 3:27 am

        FF49.0.2 x64
        dom.ipc.plugins.asyncdrawing.enabled : true
        layers.allow-d3d9-fallback : false
        at default & not changed afaik

        sorry dupe bjm October 25, 2016 at 3:12 am

      2. bjm said on October 25, 2016 at 3:12 am

        my FF49.0.2 x64 is default > dom.ipc.plugins.asyncdrawing.enabled : true and layers.allow-d3d9-fallback : false

  6. Mark Hazard said on October 21, 2016 at 2:55 am

    I got the update, but I had to flip the Asynchronous Plugin Rendering switch back to false. Otherwise, it messed up certain videos where I could hear the audio, but couldn’t see anything. I disabled Flash to solve this problem, but then I had to enable it again to view other videos, such as on the BBC. I think this is a new bug.

    1. happysurf said on October 21, 2016 at 6:26 pm

      Same for me for some Flash videos.

  7. Tom Hawack said on October 20, 2016 at 10:23 pm

    Mozilla Firefox 49.0.2 available for download from Mozilla Firefox release directory.
    No new system add-ons, the issues have been fixed by replacing default settings :
    EnableAsynchronous Plugin Rendering : dom.ipc.plugins.asyncdrawing.enabled : false->true
    Remove D3D9 Acceleration Fallback : layers.allow-d3d9-fallback : true->false

    1. pHROZEN gHOST said on October 21, 2016 at 1:14 am

      Yes, I have 49.0.2 and those settings are as stated.

  8. Robert G. said on October 20, 2016 at 9:16 pm

    I already downloaded Firefox 49.0.2:

  9. john said on October 20, 2016 at 8:26 pm

    As a heads up there are reports that Avast is removing/flagging these patches as malicious.

    1. Martin Brinkmann said on October 20, 2016 at 8:32 pm

      Good point John, yeah I saw that report as well. Hope they fix this soon.

      1. Mikhoul said on October 24, 2016 at 9:28 pm

        Moreover Martin, it will not be only update that will be pushed through this unilateral mechanism, it will be also “social experiments”, tracking/telemetry software, survey from Mozilla, anything they think you need to use or see will be pushed through System Addons.

        Surely it will be half baked since the priority at Mozilla is NOT to have a stable browser but doing anything else on the interface make insignificant changes on GUI that fundamentally brings nothing but annoy the users.

        At least if Update were seriously tested it would always be an issue since we don’t have the choice but at least it would be less prone to crashing.

        There is 3 different bugs ticket open right now on Bugzilla about this issue the first was 3 days ago and NOBODY have took over those bug, the one I’ve put last night is marked IMPORTANT and the 3 bugs are in the LIMBO.

        SO for Mozilla being able to view Video on major news website AROUND the world like TVA or BBC in UK and many others is not important since users can hear the sound it’s enough for Mozilla /S :P

      2. Tom Hawack said on October 24, 2016 at 9:16 pm

        ‘extensions.systemAddon.update.url’ is a nice find but as I see it, if you have a system add-on installed and active (not disabled with CCleaner) there’s no point in blocking its very usefulness. Better, IMO, to either delete system add-ons you don’t want (from Firefox’s install folder) and keep those you want freely updated …

        Also, to disable the update url, just replace original url with https:/ …

      3. Mikhoul said on October 24, 2016 at 7:54 pm

        Hi Martin,

        I digged a little bit more about “system addons” automated update and I really don’t like it from what I’ve seen.

        Mozilla can push at any time “system addons” for anything they want without telling anything to the user.

        So if something break because of a pushed “System addons” to your Firefox without you changing anything on your side you will never know it was because of a change from Mozilla (Pushed update or “feature”) on your browser without telling you anything about the change.

        This is what happen RIGHT NOW with FF 49.0.2 lot of users are affected like me around the world on many website that use Flash for their video player. It make really hard to troubleshoot such issue since you don’t really know something changed inside your browser with the push updates.

        It look like the Microsoft Win10 update, you are fed updates/blobs in your browser without knowing anything about them and without the choice to refuse them. :(

        If you have a “custom setup” that for any reason require a old Firefox version you will be updated against your will and never know about why your system suddenly break.

        When I was digging I read a lot about those system addons and they will be used for lot of useless things because Mozilla say “YOU NEED THIS WE KNOW BETTER THAN YOU WHAT YOU REALLY NEED” .

        One example they intend to push a system addon to all user using 3-2 versions older Firefox that will display a big Yellow overlay over the Firefox content in the upper screen that CAN’T be dismissed till you update to the current Firefox release. It’s horrible and it’s only the beginning !

        Lot of other half-baked/half-tested update like 49.0.2 will come, moreover Mozilla will be able to push any fantasy it want and think “It’s good for you, we know better than you what you need and want” like the kind of Spyware to have your data in exchange of a sticker, a promotion for a Mozilla partner….

        The GOOD news I’ve found how to disable the push of System Addons:

        1- Open about:config
        2- Search for “extensions.systemAddon.update.url” in the search field.
        3- Add a letter in the front of the value: “” to disable it and later when you want to reactive it just remove the letter you have added in the front of the URL

        Screenshot with added letter:

        I really hope somebody will come with an addon to disable it directly with a toggle button, it would take 15 minutes to do but sadly I have not enough knowledge about Firefox addons.

        You should write something more formal about it to make user aware that from now their browser will update minor update and feature without their knowledge and consent but there is the trick with about config to prevent it from happening for power users.

      4. Martin Brinkmann said on October 24, 2016 at 8:32 pm

        Not saying this is good or anything, but Mozilla is not the only organization doing that. Google is too.I don’t like this as well from a user perspective, as I prefer to be in control of these things. With updates at least, you get a choice but with system add-ons, it appears you don’t.

        Still, I also see the use of system add-ons.

      5. Tom Hawack said on October 24, 2016 at 3:22 pm

        Not that I’m aware of (if Martin doesn’t know Papa Tom more than unlikely to knwo!)

        At this time I know only two methods to control system add-ons :

        1- Backup and delete those you don’t want in Firefox’s install folder/browser/features folder ;
        2- Use the CCleaner application / Tools / Browser plugins/Firefox which lists all plugins as well as all add-ons and — what Firefox doesn’t do in about:addons — system add-ons as well, with the possibility for enable/disable WHATEVER add-on -> Firefox developers : think about it.

      6. Mikhoul said on October 24, 2016 at 2:38 pm

        Martin: Quick question to you How I can prevent Firefox to push automatically system add-on ?

        Those updates have break mt system:

        I would prefer only update manually this way if something broke I will CLEARLY know that it is after I received an update from Mozilla.

        I’m pretty sure there is a flag in about:config but I can’t find it ?

        Regards ! :)

      7. Martin Brinkmann said on October 24, 2016 at 3:05 pm

        I have to admit that I’m not aware of a parameter that would allow you to do so. Maybe someone else?

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