YouTube does not work on latest version, besides safe mode.

[EinCB128]

I can no longer play 1440p60. I've uninstalled and reinstalled it twice, it doesn't work. I've disabled all the add-ons, it doesn't work. It also drops frames on 1080p60.
It only works perfectly when it's in safe mode. When I refresh Firefox, it works. I'm using a 2016 Acer PC with Windows 10. I've never had this problem until Firefox updated to 55.

Am I going to have to go back to an older version? How can I fix this? Thank you.

[DanRaisch]

Have you tried switching off hardware acceleration in Firefox? Tools->Options->General->Performance section.

[EinCB128]

I think that did the trick! Some questions:

1. What's the point of hardware acceleration? Why didn't it help me when it was enabled? According to Firefox, having it enabled help users, but disabling it solved my YouTube problem.

2. Firefox (and Google Chrome) are unable to play 4k at 60 frames, do I need a better graphics card? Or is Firefox unable to view videos at this resolution?

I've installed my previous extensions and so far so good! Thank you! Thank you!

[DanRaisch]

1. It can help users if their hardware can deal with it but some video cards can't.

2. Don't know the answer to that.