Fullscreen Youtube

Hi there Matt,

Welcome to Apple Support Communities.

The article below provides a lot of great information and troubleshooting tips that will resolve most issues like the one that you described, where YouTube videos are distorted in Safari on your MacBook Air.

If Safari is slow, stops responding, quits unexpectedly, or has other issues - Apple Support

Ciao.

Yeah, no. I have one extension--AdBlock--I've tried with it shut down and no joy. Of the library folders given in the above link, I have 3 of them, all empty. When you attempt to go fullscreen, it does so for a split second before chirping as it resorts to "normal" view. The screen you now have only shows the upper left quarter(ish) of what you'd see in fullscreen. I have cleared cache and cookies and checked for flash updates--everything is up-to-date.

MacBook Pro

OS X 10.10.5

Safari 8.0.8

I noticed this too, but with any fullscreen video (YouTube, Netflix, HBONow). Very frustrating, have not been able to isolate it yet, though I noticed it's only an issue in Safari. Chrome, Firefox etc work fine.