Hello,

The Refresh feature (called "Reset" in older Firefox versions) can fix many issues by restoring Firefox to its factory default state while saving your bookmarks, history, passwords, cookies, and other essential information.

Note: When you use this feature, you will lose any extensions, toolbar customizations, and some preferences. See the Refresh Firefox - reset add-ons and settings article for more information.

To Refresh Firefox:

1. Open the Troubleshooting Information page using one of these methods:
   • Click the menu button , click help and select Troubleshooting Information. A new tab containing your troubleshooting information should open.
   • If you're unable to access the Help menu, type about:support in your address bar to bring up the Troubleshooting Information page.
2. At the top right corner of the page, you should see a button that says "Refresh Firefox" ("Reset Firefox" in older Firefox versions). Click on it.
3. Firefox will close. After the refresh process is completed, Firefox will show a window with the information that is imported.
4. Click Finish and Firefox will reopen.

Did this fix the problem? Please report back to us!

Thank you.

Tyler, thanks for that info, but... I am holding out for a solution that doesn't require me to reset FF. Honestly it would be easier to switch browsers than go through the nightmare that was getting FF set the way I like it. That is to say the way FF USED to look and feel years ago, before they started moving things around and adding buttons and "features" that I hate and don't use.

I have spent days fiddling with and reading forum posts and help articles to figure out how to turn off the unneeded garbage Mozilla has been adding to FF in recent updates. I use the Classic Theme Restorer to force it to do what it ought to do anyway, i.e. let ME decide which buttons I want where. I'm not keen on going through that again.

Please, for pity's sake, tell me there is some other way to fix this without starting from scratch.

For the record, it has been working PERFECTLY FINE until this most recent "update" was forced on me.

YouTube is generally now serving Firefox users the HTML5 player instead of the Flash player; you can check which one you are getting by right-clicking the player and checking the last line of the short context menu.

You can use an extension to force YouTube to serve whichever player you prefer, assuming you have all the bits and pieces available on your system and not disabled in Firefox: YouTube Flash Video Player.

jscher2000 said

YouTube is generally now serving Firefox users the HTML5 player instead of the Flash player; you can check which one you are getting by right-clicking the player and checking the last line of the short context menu. You can use an extension to force YouTube to serve whichever player you prefer, assuming you have all the bits and pieces available on your system and not disabled in Firefox: YouTube Flash Video Player.

When I right click the vid it says it's using Flash Player. I checked youtube.com/html5 and it says that player is selected for use when available on my account. Not Sure why it isn't using it.

Can you tell me how to force this version of FF to use the html5 player? Assuming that is what you're saying I should be doing.

Hmm, that's confusing. Could this be caused by one of your extensions? For example, some video downloaders cannot work with the HTML5 player and may force Flash.

As a blanket check to rule out issues caused by extensions, you could test in Firefox's Safe Mode. That's a standard diagnostic tool to deactivate extensions and some advanced features of Firefox. More info: Diagnose Firefox issues using Troubleshoot Mode.

If Firefox is not running: Hold down the Shift key when starting Firefox.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any change in the player?

Restarted with add ons disabled (safe mode) but no change in the problem.

Recap of the problem: I open a youtube page and the vid begins to play, then stops (hangs) and after several seconds I get a message like this: "A script on this page may be busy, or it may have stopped responding. You can stop the script now, open the script in the debugger, or let the script continue.

Script: https://s.ytimg.com/yts/jsbin/…ame-vfli7VvCh/www-pageframe.js:56"

I click the "Stop Script" button and the vid plays. But the problem will occur every time I play a new video.

I really appreciate this help, by the way. So.. what now?

Are you sure protected mode is disabled? Firefox has a hidden setting for this now, in case you were manually editing an mms.cfg file:

(A) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(B) In the search box above the list, type or paste flash and pause while the list is filtered

(C) Double-click the dom.ipc.plugins.flash.disable-protected-mode preference to switch its value from false to true.

This might not take effect until all Flash has been unloaded for a few minutes, or you close Firefox.

Firefox can play OGG and WEBM videos natively in the HTML5 player without external assistance, but uses Windows Media Foundation to play MP4 video. There are some settings in Firefox to disable that; users who preferred to easily download MP3s sometimes changed those settings. Here's how you can check yours:

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the search box above the list, type or paste media and pause while the list is filtered

(3) {for Windows newer than XP} If the media.windows-media-foundation.enabled preference is bolded and user set to "false", double-click it to switch it to true

(4) {for Windows XP} If the media.directshow.enabled preference is bolded and user set to "false", double-click it to switch it to true

If you changed these settings, does that make any difference in what player YouTube serves you? I'm not sure whether the change takes effect immediately or after you exit Firefox and start it up again.

Users in Europe may need the Windows Media Feature Pack for Windows 8.1, but if your Windows came with Windows Media Player, then that probably does not apply to you. See:

• https://support.microsoft.com/en-us/kb/2929699
• https://www.microsoft.com/en-US/download/details.aspx?id=40744

Ok, I re enabled protected mode, closed FF. Opened FF and disabled protected mode again, closed and reopened FF... And now it appears to be working.

So, is it ok to leave protected mode disabled, or is that a bad idea and only a temp solution?

Also, I got confused about the second portion of your message. It sounded like it is saying how to disable HTML5 and force Flash, but my problem is I'm using Flash and prefer HTML5. Or did I misread that entirely? Sorry, I'm something of dimwit about tech things.

But for now at least, FF is more or less working, so I am marking this one solved. I will simply hope the next update (grimace) corrects whatever caused this version to mishave. Thanks to all for the assistance and patience.

murrayelec said

So, is it ok to leave protected mode disabled, or is that a bad idea and only a temp solution?

In a perfect world, this feature would work for all users. The protected mode splits Flash media into multiple external processes that run with a lower privileges, so they are less able to change stuff on your system or interfere with other programs. This is a smart idea, but problems with this feature have persisted since it was introduced in June 2013, so I don't know whether Adobe is even working on solving them any more. Maybe someone has done some research on alternative workarounds, but honestly I have stopped looking.

It sounded like it is saying how to disable HTML5 and force Flash, but my problem is I'm using Flash and prefer HTML5.

Those steps are to re-enable MPEG decoding if you disabled it before; I probably didn't explain it clearly enough. But you do want the default settings for those preferences if you want the best chance of playing MP4s in the HTML5 player.