Please try the following:

1. Type about:config in the Firefox address bar
2. Locate the media.windows-media-foundation.enabled boolean
3. Set the value to false
4. Restart Firefox
5. Reload Vine while bypassing the cache by holding down the Shift key and click the Reload button

Let us know if this fixes the issue.

check this:

• see if there are updates for your graphics drive drivers

https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

• disable protected mode in the Flash plugin (Flash 11.3+ on Windows Vista and later)

https://forums.adobe.com/message/4468493#TemporaryWorkaround

• disable hardware acceleration in the Flash plugin

https://forums.adobe.com/thread/891337 See also:

• http://kb.mozillazine.org/Flash#Troubleshooting

Thank you for both your suggestions. Wesley Branton: I followed your instructions and when I restarted Firefox and tried to play a Vine it wouldn't play. Instead a message appeared saying that my browser wouldn't support a video player or play videos.

FredMcD: I checked for updates for my graphics drivers, found 2, downloaded them and restarted Firefox. Vines still won't play. I disabled hardware acceleration in the Flash plugin, restarted Firefox again and Vines still won't play. I didn't try the "disabled protected mode" method because the directions at the link you posted seemed too complicated, at least to me.

I appreciate all your suggestions and thanks again for trying to help. If you have any other suggestions for this problem or anyone else has any please post them. Thanks again.

Also, what's weird is that the Vines won't play on Twitter but they will play on Vine's website. Videos will play on Instagram's site too, just not on Twitter.

"To disable Protected Mode, add the following line to your mms.cfg file located in folder:

Windows 32bit: C:\windows\system32\macromed\flash Windows 64bit: C:\windows\syswow64\macromed\flash

ProtectedMode=0"

With Firefox off, open your file browser to the proper folder (above). Look for a file called; mms.cfg

If there is no such file, create it by; Right click an empty area in that folder and select New > Text Document. When the new file is created, name it mms.cfg

Open the file with a text editor. On the first line, place this; ProtectedMode=0 by itself. Don't remove anything from the file. Now save the file, and close the editor.

This sounds like a problem with the HTML5 media player and not with the flash plugin.

You can check for issues with media support on windows.

• https://support.mozilla.org/kb/fix-video-audio-problems-firefox-windows

Check that these prefs are set to true (default):

• media.windows-media-foundation.enabled
• media.directshow.enabled

Thanks to everyone for their suggestions but nothing seems to be helping this problem. Vines still won't play on Twitter no matter what I do.