Do you mean this page: http://www.mozilla.org/en-US/firefox/central/

The small video should play natively in Firefox (HTML5 video), but if that isn't available, it falls back to the Flash player. If you click the video to start it, then call up the context menu for the player -- Mac equivalent of right-clicking the player area -- can you tell from the menu whether it is Firefox playing the video or whether Flash is involved?

If it's Firefox, there should be a menu item to Copy Video Location. Can you do that and paste the file name here to show what format is being played? I get a URL ending with "Browsing-Basics-640.webm".

Thanks for your reponse. Yes, that is the page and Copy Link Location shows: http://www.mozilla.org/en-US/firefox/central/# Cheers

Could you try Copy Video Location? You have to start the video before that shows up on the menu.

Firefox should play a WebM video natively if you open such a video link via the location bar.

• http://videos-cdn.mozilla.net/brand/Mozilla_Firefox_Manifesto_v0.2_640.webm

• http://www.mozilla.org/en-US/firefox/video/

When the page opens I get a message that plugins are missing. Clicking on Install Missing Plugins comes up with Unknown Plugin (video/mp4); Manual Install takes me to the DivX Install page - DivX is up to date.

Once I start the video, Copy Video Location is not an option with Control-click. I can access Page Source, which seems to suggest that Flash is not installed although the Plug In check page says it is.

Is this extract from Page Source helpful?: div class="video-player-no-flash" This video requires a browser with support for open video or Flash.

There doesn't seem to be an option here to be able to attach the whole Page Source as a text file.

Cheers.

Same messages when I open via:

http://www.mozilla.org/en-US/firefox/video/

What happens if you open the WebM link that I posted above via the location bar?

Why don't you try updating to Firefox 16.0.1 to see if that works?

• https://support.mozilla.org/kb/update-firefox-latest-version

The Firefox version that you currently run is no longer supported with security updates.
It is important to update Firefox and add-ons to the latest versions to get the latest bug fixes and security updates.

I replied above to your question re opening http://www.mozilla.org/en-US/firefox/video/ Same result.

I should have been receiving any important security updates if I don't want to upgrade - I do for the OS.

Upgrading in the past has meant a lot of work fixing up my Toolbars and menus and it generally takes more time than it's worth.

I just started up in Safe mode and the video works!

Does this mean a clash of plugins? Which one(s) should I remove?

(Incidentally, I had previously tried with AdBlock off but that didn't solve the problem.)

Thanks for all your suggestions.

Cheers.

If it does work in Firefox Safe-mode then disable all extensions (Tools > Add-ons > Extensions) and then try to find which is causing it by enabling one extension at a time until the problem reappears.

Close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit")

See also:

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Try to disable hardware acceleration in Firefox.

• Firefox > Preferences > Advanced > General > Browsing: "Use hardware acceleration when available"

Disabling hardware acceleration didn't work, but I'll try disabling all extensions and then enabling one at a time.

Thanks for your help.

Cheers.

Hi again

I disabled:

"DivX Plus Web Player HTML5

and video now plays.

Cheers.