you tube quality menu unavailable
For years, you tube viewed on firefox presented a video quality menu, on which one could select up to 720 or 1040 resolution. Starting a week ago, that menu changed and only allows 360p. Yet, on my SlimJet browser, I still get the menu that allows me to select 720p, etc. I have screenshots of the menus on slimjet and mirefox proving this, but your image uploader is absurdly slow, so I cancelled trying to attach the screenshots., My flash plugin is up to date, and I reinstalled it just in case. No improvement.
You can upload screenshots on an external site like Imgur, it is very easy to use it. Next paste the URL here.
I assume the menu change in YouTube videos is related to switching from Flash player to HTML5 player, which is itself due to upgrade to Firefox 40 (note that Firefox doesn't choose the player, Google make it).
See this other similar thread for more information: After FF40 update I cannot use Flash player on youtube, video quality is up to 360p.
Until Firefox 39, YouTube served Windows XP users the Flash-based player. Starting in Firefox 40, YouTube now serves Windows XP users the HTML5-based player, which is very unfortunate because on Windows XP, Firefox can't decode MP4, so you get WebM 360p as your only format choice.
Assuming this is the problem -- you can right-click the player and look at the last line of the short context menu to confirm the player being used -- here are two possible workarounds:
(1) Use an add-on to force YouTube to serve you the Flash player
There are at least two extensions for this, you only need one:
(2) Use an add-on to tell YouTube you're still running Firefox 39
(A) Install the extension https://addons.mozilla.org/firefox/addon/ua-site-switch/ which admittedly has a confusing interface.
(B) Select and copy the old user agent identification for Firefox 39:
Mozilla/5.0 (Windows NT 5.1; rv:39.0) Gecko/20100101 Firefox/39.0
(C) While on a youtube.com page, click the little drop-down triangle for ua-site-switch and paste the old user agent string and then press Enter to save it
(D) Then reload YouTube bypassing cached files (Ctrl+Shift+r)
(E) Repeat B & C on https://www.youtube-nocookie.com/ to apply the hack to embedded videos