If you are India, please check to make sure that you are not affected by the new changes made. Please make sure Flash block is turned off if you have that installed.

It is also possible to temporarily block the Flash player and use HTML5 video player.

Please post back with your results! It can help other users.

I don't know what you mean by "if you are india". I use the stable release channel, if this was your question. As I wrote it doesn't matter if I start in protected mode (without add-ons) or not. Thus I dont believe any Add-Ons like flashblock cause my issues.

I already switched on html5 player on youtube. I additionally blocked the flash plugin. This didn't change anything.

So except blocking the flash plugin I already checked your suggestions. Doublechecked them right now and still no change.

Thanks for your help, but the issue is not resolved yet. Any further ideas?

Oh, not what I meant at all. There was a post from the India community about a new issue where many popular sites were blocked and youtube was affected. See this post in the forum: https://support.mozilla.org/en-US/for.../710463?last=60706

You can also try your drivers Upgrade your graphics drivers to use hardware acceleration and WebGL as well as right click on the flash player and reset the global settings for storage.

Clear the cache and cookies only from websites that cause problems.

"Clear the Cache":

• Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: "Show Cookies"

You can also try to clear all the cookies including data stored in DOM storage by specifying "Everything" to remove the cookies.

• https://support.mozilla.org/kb/remove-browsing-search-and-download-history

You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History > Show All History" or "View > Sidebar > History") or via the about:permissions page.

Using "Forget About This Site" will remove all data stored in Firefox from that domain like bookmarks, cookies, passwords, cache, history, and exceptions, so be cautious and if you have a password or other data like bookmarks from that domain that you do not want to lose then make sure to backup this data or make a note.

You can't recover from this 'forget' unless you have a backup of the involved files.

It doesn't have any lasting effect, so if you revisit such a 'forgotten' website then data from that website will be saved once again.

Thanks a lot cor-el. Your hints fixed my problem without the need to configure a new profile from scratch. Saved me a lot of time =)

Cannot tell you what exactly did the job, as I tried your three hints all at once. Cleared the cache and deleted the youtube.com specific cookies plus forgot everything about the website (my guess is this did the magic but I don't really know which steps are included there.)

Plus this feature was new to me and is now a new tool in my toolbox.

Cheers, watnuss

Okay I was too fast to call this off.

There is a new situation. After forgetting the website playing the videos worked. Then after logging in with my google account to youtube I get the same error again. Logging out again won't help; the error still persists. After forgetting about youtube I can view youtube videos as long as I don't log in again.

So in my opinion a really strange problem. How can my profile settings break playing videos? Any ideas on what settings this might be? Any other ideas?

thanks for your help so far

Does clearing the cache work?

Does it work if you open YouTube in a Private Browsing mode window?

If it still stops working if you login then try to close and reopen the Private Browsing mode window.

What are the cookie settings?

Does clearing the cache work? --> no Does clearing cookies work? --> no Does forgetting youtube work? --> yes

Does it work if you open YouTube in a Private Browsing mode window? not logged in in normal mode, viewing in private mode --> yes logging in in private mode, viewing in private mode --> no not logged in, open private browsing window, log in in normal, view in private browsing --> yes log in in normal, then open private browsing window and view --> no

If it still stops working if you login then try to close and reopen the Private Browsing mode window. --> see above

What are the cookie settings? its set to forget on closing the browser and I use self destructing cookies to whitelist choosen sites. Youtube is set to "after closing tab"

Your questions are quite target-oriented. Do you have something in mind?

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

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

As I mentioned in my opening post safe mode (it's what I meant with protected mode/starting without extentions.) doesn't resolve the issue. Vidoes won't be played. I nevertheless double checked this and videos still won't play.

You may have to reset (delete) cookies if you have extensions that deal with cookies. It is weird though that a cookie problem would persist in Private Browsing mode.

Private Browsing mode disables the disk cache and gives a new set of cookies, so if PB mode doesn't help then the problem should be different (no cookies or local storage or cache).

Does the new profile work regardless of being logged on or not?

That is a interesting idea. Just checked it and surprisingly youtube works on a newly created profile even if I log in to the same account.