Youtube currently uses the HTML5 player.

https://support.mozilla.org/en-US/kb/fix-common-audio-and-video-issues?redirectlocale=en-US&redirectslug=Video+or+audio+does+not+play

https://support.mozilla.org/en-US/kb/fix-common-audio-and-video-issues

FredMcD said

Youtube currently uses the HTML5 player. https://support.mozilla.org/en-US/kb/fix-common-audio-and-video-issues?redirectlocale=en-US&redirectslug=Video+or+audio+does+not+play https://support.mozilla.org/en-US/kb/fix-common-audio-and-video-issues

Its not that the video or audio isnt playing the preview box that can help when scanning through a youtube video is black. Is there any other more specific fix? I updated Java and this did not fix it

Please check out the links I posted.

FredMcD said

Please check out the links I posted.

I did check the links all they say is update. everything is up to date

Is the Shockwave Flash plugin used or the HTML5 media player?

You can check via the right-click context menu of the player area what kind of media player is used. A Flash based player shows a context menu with the Flash version.

Does it help if you change the resolution via the cogwheel button on the player?

cor-el said

Is the Shockwave Flash plugin used or the HTML5 media player? You can check via the right-click context menu of the player area what kind of media player is used. A Flash based player shows a context menu with the Flash version. Does it help if you change the resolution via the cogwheel button on the player?

It says adobe flash player when I right click the youtube video. changes the resolution doesnt fix it.

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• Do NOT click the "Refresh Firefox" button on the Safe Mode start window

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

You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• Hold down the Shift key and left-click the Reload button
• Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• Press "Command + Shift + R" (Mac)

cor-el said

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• Do NOT click the "Refresh Firefox" button on the Safe Mode start window

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

You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• Hold down the Shift key and left-click the Reload button
• Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• Press "Command + Shift + R" (Mac)

Thanks Putting it in Safe Mode has allowed the preview box to come back! but idk if it will work when I go back with the addons I have.

cor-el said

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• Do NOT click the "Refresh Firefox" button on the Safe Mode start window

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

You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• Hold down the Shift key and left-click the Reload button
• Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• Press "Command + Shift + R" (Mac)

I disabled the extensions 1 by one narrowing down what was causing it and I found out it is "Youtube Flash Video Player"? I thought this is required to play youtube videos?

cor-el said

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• Do NOT click the "Refresh Firefox" button on the Safe Mode start window

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

You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• Hold down the Shift key and left-click the Reload button
• Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• Press "Command + Shift + R" (Mac)

I figured out the problem I installed that extension to get rid of the fade in and fade out of full screen youtube videos but it also got rid of the small preview box.

In another recent search I found out a way to fix this without and extension: https://support.mozilla.org/en-US/questions/1092730

THANKS! for helping me fix this. I always use the preview box when following tutorials or other stuff. Glad I fixed it!