I had this issue and a close and relaunch solved the issue recently, but I though it was a glitch on my end, maybe it was not.

So, Try creating a new Firefox Profile and try to see if that helps for troubleshooting purposes.

in the address bar type: about:profiles

You will see a list of ALL Firefox profiles. Please note your current profile in use first.

Create New Profile Button at the top. Create a new profile in 3 easy steps following the steps.

Your new profile will appear at the bottom , just choose launch profile in new browser this way you will not have to uninstall anything.

Try that to see if youtube works in there before messing with too much.

You will always have your default Firefox profile in tact

So I tried that, but same result, still the black screen with loading circle in middle :(

You know you could try uninstall and re-install from the actual installer off the ftp site:

https://ftp.mozilla.org/pub/firefox/releases/103.0/

You will of course have to set up any special setting, i know its a pain but I thought I would put it out there.

I am also going to ask another dumb question but did you try a shutdown and re-boot , or see if any other foxfire processes were running ?

You know you could try uninstall and re-install from the actual installer off the ftp site: https://ftp.mozilla.org/pub/firefox/releases/103.0/ You will of course have to set up any special setting, i know its a pain but I thought I would put it out there. I am also going to ask another dumb question but did you try a shutdown and re-boot , or see if any other foxfire processes were running ?

First step was a restart of my PC to make sure it wasn't the computer, I guess I will try a re-install again and see anything changes using the FTP version.

You know you could try uninstall and re-install from the actual installer off the ftp site: https://ftp.mozilla.org/pub/firefox/releases/103.0/ You will of course have to set up any special setting, i know its a pain but I thought I would put it out there. I am also going to ask another dumb question but did you try a shutdown and re-boot , or see if any other foxfire processes were running ?

So after uninstalling, and doing a fresh install, it still seems to not work? Same thing black screen with a spinning circle. I really am at a loss on this, it just randomly started yesterday :(.

I am assuming any Youtube video?

https://ftp.mozilla.org/pub/firefox/nightly/2022/07/2022-07-28-09-32-33-mozilla-central/firefox-105.0a1.en-US.win64.installer.exe

Try installing the latest nightly. This will install in a completely different directory and use a completely new profile.

If that still does not work there are bigger issues going on somewhere else because I am at a loss as i have had to wipe out a profile or install in the past many times because they get corrupt, but this seems odd to me.

https://ftp.mozilla.org/pub/firefox/nightly/2022/07/2022-07-28-09-32-33-mozilla-central/firefox-105.0a1.en-US.win64.installer.exe Try installing the latest nightly. This will install in a completely different directory and use a completely new profile. If that still does not work there are bigger issues going on somewhere else because I am at a loss as i have had to wipe out a profile or install in the past many times because they get corrupt, but this seems odd to me.

Same thing :(

The last thing I can think of is a new Windows local profile to see if it is a machine profile or Machine Global issue.

The last thing I can think of is a new Windows local profile to see if it is a machine profile or Machine Global issue.

But if it was a windows issue, wouldn't that also cause the issue in Chrome and Edge? Videos play just fine in both of those.

Since i did not develop any of the browsers I do not know how they render things. They may have different ways of handing video , i simply do not know. they use different engines.

I know that I work in an Enterprise environment and have been for 17 years. I know that creating a new user profile does resolve some issues and, the machine is just fine, just individual user profiles are the issue so no need to place a new machine or re-image it. They have resolved anything from office issues to weird issue I cannot explain. That is usually one of the first things we try is to log on as ourselves and see how the application works under ourselves because if it still fails then it will not work for anyone who logs onto a machine and that is usually a global issue.

I am not saying it will positively resolve it but you have nothing to loose right now. Once again Chromium based browsers have a different engine from webkit(apple) and Mozilla's Gecko

Since i did not develop any of the browsers I do not know how they render things. They may have different ways of handing video , i simply do not know. they use different engines. I know that I work in an Enterprise environment and have been for 17 years. I know that creating a new user profile does resolve some issues and, the machine is just fine, just individual user profiles are the issue so no need to place a new machine or re-image it. They have resolved anything from office issues to weird issue I cannot explain. That is usually one of the first things we try is to log on as ourselves and see how the application works under ourselves because if it still fails then it will not work for anyone who logs onto a machine and that is usually a global issue. I am not saying it will positively resolve it but you have nothing to loose right now. Once again Chromium based browsers have a different engine from webkit(apple) and Mozilla's Gecko

So after making a new profile on my PC and setting it as admin and logging in, I opened firefox, and well, same thing just a black screen with the loading circle. I am at a complete loss at this point.

So I finally figured it out! I forgot along time ago I set my DNS to use Cloudflares (1.1.1.1) DNS, I changed that to the Google DNS (8.8.8.8) and boom YouTube now works again..... Crazy how something so small can cause a problem.

all that work we did lol.... I use cloudflare and do not have any issues I have that set up by default on my router with the backup 1.0.0.1 and i never had an issue... that's odd