Youtube videos only open with quicktime--small screen/no audio. Flash works with Safari, not Firefox.
I've updated flash, reset Firefox, restarted Mac. Youtube videos will not load with Flash. They open with Quicktime in a 1x2 inch box of low res images with no audio.
Alla svar (1)
Open up your preferences/Options and open up applications. From here check the preferences for youtube files. In about:permissions you can check the preferences for youtube.com as well.