Youtube won't play with hardware acceleration
YouTube won't start playing in Firefox. No add-ons enabled. The page is fully loaded, but clicking on Play makes nothing.
The fix is to disable "User recommended performance settings" and then disable "User hardware acceleration when available".
The problem is that hardware acceleration is enabled by default. In Edge or Chrome hardware acceleration is also enabled but it won't break YouTube.
Wšykne wótegrona (1)
Is Chrome actually using hardware acceleration for video decoding though? Does 4K video play smoothly with minimal CPU?
Try updating your graphics drivers from the manufacturer's site.
Does it still happen in a new profile? An easy way to test a new profile is to install Developer Edition and see if it happens there or refresh your existing profile.