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Video wont play in firefox 20

  • 31 replies
  • 51 have this problem
  • Last reply by jscher2000

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Videos wont play on yahoo, youtube, ect. I have flash player 11.6. Videos will play with IE and Chrome.

All Replies (20)

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Did it work correctly in Firefox 19?

Your plugin list shows two different versions of the Flash plugin. This may not impact your problem, but you should delete the older one for security reasons. On Windows 7x64 it can be found here, so I'm guessing this will be true for Windows 8x64 as well:


You want only the latest NPSWF32 DLL file, which as of this moment is:


Delete any earlier NPSWF32files.

Do you use the AdBlock Plus extension? There have been some reports that YouTube doesn't work unless you create an exception.

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yes i worked fine with firefox 19.

No i don't use adblock.

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i deleted all earlier NPSWF32 files and that did not work either.

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I assume Flash works on Adobe's test page:

I assume RealPlayer/RealDownloser is up-to-date, or you probably would have had issues in earlier versions of Firefox.

Do you have any extensions? You might check for updates. If that doesn't help, you might try disabling them to see whether there is a conflict.

  • Updating

orange Firefox button (or Tools menu) > Add-ons > "gear" icon > Check for Updates

  • Bypassing extensions

A standard diagnostic to bypass interference by extensions (and some custom settings) is to try Firefox's Safe Mode.

First, I recommend backing up your Firefox settings in case something goes wrong. See Back up and restore information in Firefox profiles. (You can copy your entire Firefox profile folder somewhere outside of the Mozilla folder.)

Next, restart Firefox in Firefox's Safe Mode (Diagnose Firefox issues using Troubleshoot Mode) using

Help > Restart with Add-ons Disabled

In the dialog, click "Start in Safe Mode."

Does Flash work any better?

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nope it does not work in safe mode either. Every plug in is up to date. I tried that first.

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Thanks. The plugins and extensions update through different mechanisms, so I wasn't sure that you had checked the extensions.

Could you describe what you see: is it just a black rectangle? Firefox isn't reporting a plugin crash?

Not sure whether this article has any new ideas: Flash 11.3 doesn't load video in Firefox.

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Firefox /flash player Issue since V 10 I remember searching a lot about it in the time that all other browsers are working properly fine but firefox .

It keeps stopping or playing a vid without sound I have tried everything in order to solve this problem I thought I have right after resetting firefox but the problem still remains , Don't know it might be plugin issue !

NPSWF32_11_7_700_169.dll the latest update of shockwave flash 11.7.700.169

There was a huge conflict when I got the previous version running with this one but after I have disabled v . Youtube videos are playing smoothly and all was fine until this past week , Don't know what really went wrong ...

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I have the same problem of q8marronglace, videos were playing smoothly and now they keep stopping. I have adblock plus but I don't see why I should add exception to see ads when the main point was not to.

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Hi q8marronglace and AzeExMachina, what OS are you running?

This is some standard guidance that addresses the most common issues:

(1) Disable hardware graphics acceleration in Firefox and in Flash

(A) In Firefox, un-check the box here and restart:

(WIN) orange Firefox button (or Tools menu) > Options > Advanced
(MAC) Firefox menu > Preferences > Advanced
(LINUX) Edit menu > Preferences > Advanced

On the General min-tab, uncheck "Use hardware acceleration when available"

(B) In Flash, see this support article from Adobe:

(2) Disable protected mode (Win Vista & Win 7 & maybe Win 8)

See this support article from Adobe under the heading "Last Resort": Adobe Forums: How do I troubleshoot Flash Player's protected mode for Firefox?

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Hi jscher2000 and thank you for your response and your help

Well my OS is win7 64bit , FF 20.0.1 , flash 11.7.700.169 No 1 , A and B (Done) No 2 , "Last Resort" I don't see why do I have to go back to Flash Player 11.2 when I always like to keep my sys updated its not a flash problem as I said other browsers are working perfectly fine but FF , So I won't edit the mms.cfg file as it says " We strongly recommend that Protected Mode is manually enabled once this issue is resolved. " So it seems that this point it may or may not be helpful I'll stick with the the first step and just disable hardware graphics acceleration and will try that for a while and will get back here with my feedback .

The problem is FF/Flash "together" Flash is working fine with other browsers and FF is working fine but together there is a historic issue !

Thanks again for your effort

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Mine too is win7 64bit, FF 20.0.1 and flash 11.7.700.169 I've done the first point, the problem does not disappear, also I'm not that inclined to disable the protected mode. I concur with q8, the problem is in FF+Flash, Flash is working fine.

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Having I believe the same issue as others. The video begins to load, gets about 2 seconds in, stops, reverses, restarts. Then puts up the error message.

It specifically seems to be videos with audio as I watched a video with no audio file attached successfully yesterday.

I run Windows Vista and the latest version of FF. Have made sure to update Flash.

I've done as many of the steps above as I understand (not being super geeky). Nothing seems to help.

The problem seems to be FF working with Flash. So --to me--seems that FF needs to fix this!

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Error playing Yahoo videos Yahoo Video seriously struggles to load and give error everytime I try to play. I have latest version of Adobe flash player installed and it works well for most of the other sites. So its a problem only related to Yahoo Videos site. Kindly do something on this. Thank you.

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PC Info: OS Win 7 64bit Shockwave flash 11.7.700.169

Sorry for the delay as promised to write my Feedback about jscher2000 solution .

Well for starter right after doing step (1) A and B which are :

"(1) Disable hardware graphics acceleration in Firefox and in Flash

(A) In Firefox, un-check the box here and restart:

(WIN) orange Firefox button (or Tools menu) > Options > Advanced (MAC) Firefox menu > Preferences > Advanced (LINUX) Edit menu > Preferences > Advanced

On the General min-tab, uncheck "Use hardware acceleration when available"

(B) In Flash, see this support article from Adobe: "

And avoiding step 2 :

"(2) Disable protected mode (Win Vista & Win 7 & maybe Win 8)

See this support article from Adobe under the heading "Last Resort": Adobe Forums: How do I troubleshoot Flash Player's protected mode for Firefox? "

My problem remains for two days until updating the latest Shockwave flash update 11.7.700.202 on May 15 I realize my problem was solved all youtube videos are working perfectly fine so I went back to undo the two step A .

Update: When I re -Enable Hardware Acceleration the videos takes some time to load so it loads and stops again so I'll keep that option as jscher2000 said and uncheck the Enable Hardware Acceleration .

disabling hardware acceleration. Right-click the Flash Player logo below, choose Settings from the context menu. Deselect Enable Hardware Acceleration (on the Display tab), then and click Close.

see this post:

PS : Before all that please read my 1st post which I mention that I did RESET my FF and have installed a fresh ads ons and also make sure that you don't have any previous version of Shockwave that might cause a conflict with your latest version and remove or disable it .

I hope this would be helpful Thanks

Modified by q8marronglace

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Come on, Mozilla, the Yahoo video problem lies within Firefox. Many hundreds of Firefox users, perhaps thousands, can not play videos in any of their Yahoo sections.

In our case, Firefox + Yahoo video problems started as far back as of version 19, but extends to the current version 23 we have installed on our Win 7 64bit Intel machines.

IE 10, Chrome and other browsers play the Yahoo videos correctly. We used to suspect that perhaps Yahoo wanted MS's Silverlight garbage installed,but it was tested and that was not the issue. Yahoo Corporate has researched, and their corporate programmers feel strongly there's a problem in Firefox

PLEASE...Quit playing "around the mulberry bush" games and FIX FIREFOX.

P.S.: This grey message color is one of the most repulsive hard to read that I have ever seen in nearly 20 years. Someone IS playing a joke on us, right ?

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None of the solutions given above have worked. It is problem in every system I have used. I have tried in multiple Firefox versions in OS like Windows XP, Windows 7 and linux - Ubuntu. But problem remains the same. All plugins are updated.

Let us know what can be done. Thank you in advance.

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I am attaching the 2 screenshots.

One more thing, I am having proxy server with authentication for my internet connection. I guess these can help you for debugging.

Here is the troubleshooting information.

 Application Basics
       User Agent
       Mozilla/5.0 (Windows NT 5.1; rv:16.0) Gecko/20100101 Firefox/16.0
       Profile Folder
         Show Folder
       Enabled Plugins
       Build Configuration
       Crash Reports
       Memory Use
       Adblock Plus
       Download YouTube Videos as MP4
       Easy YouTube Video Downloader
       AVG Safe Search
       AVG Security Toolbar
       Microsoft .NET Framework Assistant
       Skype extension for Firefox
 Important Modified Preferences
       Adapter Description
       NVIDIA GeForce 8600 GT
       Vendor ID
       Device ID
       Adapter RAM
       Adapter Drivers
       Driver Version
       Driver Date
       WebGL Renderer
       Blocked for your graphics driver version. Try updating your graphics driver to version 257.21 or newer.
       GPU Accelerated Windows
       0. Blocked for your graphics driver version. Try updating your graphics driver to version 257.21 or newer.
       Incremental GC
       Prevent Accessibility
 Library Versions
       Expected minimum version
       Version in use
       NSS Basic ECC Basic ECC
       NSS Util
       NSS SSL Basic ECC Basic ECC
       NSS S/MIME Basic ECC Basic ECC
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Hi josephrot and rajhanschinmay, there are some other threads on the "Yahoo-only" video issue. It seems particularly intractable on Windows 8 but also has been reported by some Windows 7 users:

I am not able to replicate this problem on Windows 7 in a new "blank" profile. (A new profile picks up all your plugins, but no other add-ons and all settings are default.) Can you try the new profile test?

Exit Firefox and start up in the Profile Manager by pasting the following into the search box on the Windows Start menu and pressing Enter:

firefox.exe -P

Click the Create Profile button and accept the suggested location. (To avoid data loss do not choose the location of any existing folder containing data.) Then Start Firefox using the new profile. (More info on the Profile Manager: Profile Manager - Create, remove or switch Firefox profiles)

Any difference on Yahoo?

After testing, to switch back to your regular profile, exit Firefox, start up the profile manager, select your regular profile, and Start Firefox.

I recommend not deleting any profiles without first making a backup of all of them, just in case something were to go wrong during the deletion process.

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Thanks for the reply and yet another testing possibility.

1. The problem also replicates in Windows 7 64bit, with latest Updates, and without the Updates, ditto in Win 7 32bit machines.

2. The problem has no relation to what profile we use. Have tested.

3. The problem has no relation to the anti-virus product in use. Have tested. Depending on machine, we use AVG 2013 or MS Essentials.

4. There is no proxy server in operation. Even if there was, the Yahoo video should execute properly in the FF browser.

Again, over and over and over: Mozilla Firefox has a possibly major problem. If the problem is seen in Yahoo videos, that means it may well be a problem that will be seen on other sites.

SIDE NOTE: Here's a "Yahoo video" that is NOT Yahoo in nature!

It's actually a YouTube Flash video playing on the Yahoo page:

This Yahoo video not playing in FF browser problem is NOT seen using other browsers on the same or different machines.

Joe R. / Knoxville, TN

Modified by josephrot

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If you use extensions (Firefox/Tools > Add-ons > Extensions) that can block content (e.g. Adblock Plus, NoScript, Flash Block, Ghostery) then make sure that such extensions aren't blocking content.

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Firefox/Tools > Add-ons > Appearance).

  • Do NOT click the Reset button on the Safe Mode start window.
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