When I click on the full screen button on YouTube, I tend to lose all the built up video buffer. That can be pretty annoying when you’re on slower internet connections. Anyway, turns out the problem is because YouTube automatically increases the resolution when we click on the ‘full screen’ button leading to a restart of the buffering process.
This can be solved by signing into your youtube/google account and then making a change under ‘Account’.
Go to Account Settings>Playback setup and then choose (*)I have a slow connection. Never play higher-quality video.
See picture below –
Enjoy video watching!