Many site issues can be caused by corrupt cookies or cache. In order to try to fix these problems, the first step is to clear both cookies and the cache. Note: This will temporarily log you out of all sites you're logged in to. To clear cache and cookies do the following:

1. Go to Firefox > History > Clear recent history or (if no Firefox button is shown) go to Tools > Clear recent history.
2. Under "Time range to clear", select "Everything".
3. Now, click the arrow next to Details to toggle the Details list active.
4. From the details list, check Cache and Cookies and uncheck everything else.
5. Now click the Clear now button.

Further information can be found in the Clear your cache, history and other personal information in Firefox article.

Did this fix your problems? Please report back to us!

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

• Do NOT click the Reset button on the Safe mode start window or otherwise make changes.

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

Well, I tried everything both of you mentioned above and I still cannot watch any video or movie trailer on Yahoo's website. I can watch flash video on other websites with FF. I can also watch the Yahoo videos with IE. This really has me aggravated to say the least. Like I mentioned in my first post...everything is up to date...Windows, all the FF plugins, everything. I have uninstalled FF, went to an older version of FF, uninstalled & reinstalled both Flash & Java. This is very strange to say the least. I have also tried with the Windows firewall turned off.

Please read the post above this one first. I just tried watching a Yahoo video on Chrome without any luck either. All I got was a black screen with a rotating circle in it...just like FF. This leads me to believe that there is a problem with my Flash plug-in...or at least a permission attached to it. I even tried a system restore to 3 weeks ago w/o any luck. I have uninstalled/reinstalled Flash. Tried older versions. This makes no sense. I have to PC's. Identical OS (Win 7), identical browser versions, plug-ins...you name it...there the same.

Google Chrome comes with its own Flash plugin (pepflashplayer.dll) and shouldn't have problems with the Flash plugin that Firefox uses. So if Flash isn't working there as well then you may have other problems.

Try to boot the computer in Windows Safe mode with network support (press F8 on the boot screen) as a test to see if that helps.

Well, I booted into Windows Safe mode w/ networking and neither FF nor Chrome would play Yahoo videos on my laptop. I went to other sites and played flash videos just fine w/ FF & Chrome while in Windows Safe mode. Very strange to say the least? Any other ideas? By the way, thanks for the help. Very much appreciated.

Try to "disable the hardware acceleration" in the Flash Player.

• http://helpx.adobe.com/flash-player/kb/video-playback-issues.html

See also:

• https://support.mozilla.org/kb/keep-flash-up-to-date-and-troubleshoot-problems

Flash "Display settings" window:

• http://www.macromedia.com/support/documentation/en/flashplayer/help/help01.html

Yea...I already tried disabling hardware acceleration. That didn't work either. Whatever the problem is, it is common to both FF as well as Chrome.

Have you tried clicking again in the swirling arrow ? I did a couple times and noscript (I believe) came up with a proceed or not message and it continued to play after that. And for whatever reason, it started working in Chrome after that.

I tried clicking again in the swirling arrow and nothing happened. Funny thing about this problem...it only happens with Yahoo videos when viewed with both Firefox and Chrome. The only way I can view Yahoo videos is with Internet Explorer. I am over it. Just not worth the effort anymore.

I am having the same problems. I tried safe mode, clearing cookies, and even disabling hardware acceleration. I don't have Chrome installed, but Yahoo videos do work on IE.

Is this problem being worked on?

Well, as of today I still cannot view Yahoo videos in Firefox on my laptop. On a side note, I managed to figure out how to get the Yahoo videos to play in Chrome. I had to go into Chrome and disable the Flash plugins. It appears the plugins conflict with Chrome's built-in flash player. I guess this will just have to go down as one of life's little mysteries.

I have more to add:

Yahoo videos work on my Windows 7 x64 laptop in Firefox with the exact same add-ons (extension) installed. Yahoo videos do not work on my Windows 8 x64 laptop, and I have no idea why. I use the Windows 8 laptop to watch Yahoo videos most often as that is the one I take to school.

Any help?

I did the same thing as wildbill98 today: I managed to view Yahoo videos on Chrome and still cannot find a way to view Yahoo videos on FF. I have to wonder FF people can help.

What kind of videos are this?

Firefox doesn't support MP4 videos via the video tag or videos encoded as H.264.

Just random videos hosted by Yahoo.

For example, a recent story posted by Yahoo: http://news.yahoo.com/blogs/power-players-abc-news/former-sen-mike-gravel-says-white-house-suppressing-112957111.html?vp=1

It will load on my Windows 7 x64 loaded with x86 Firefox, but not my Windows 8 x64 loaded with x86 Firefox.

Both have the same add-ons because I used Firefox sync to install add-ons onto the Windows 8 laptop.

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

• Do NOT click the Reset button on the Safe Mode start window or otherwise make changes.

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

I'm sorry, I should have pointed out to my earlier post. I have already tried using Safe Mode with the default theme with no luck. I have just tried it again, and still no luck with the Yahoo videos.

Any other suggestions?

EDIT:

I want to add that videos work perfectly fine on my Windows 7 x64 laptop with Firefox.

Bump.

No solution to this?

I know the feeling... I have to use IE on my Windows 8 laptop now. Certainly hope Firefox people will fix this one of these days...