YouTube Freezes in Safari Unless You Move the Mouse

There was an issue where whenever I would try to view YouTube videos in Safari, the video would freeze frequently (while audio continued to play in the background) - the only way to prevent this was to move the cursor over the video. I have the latest version 12.0.3 and latest MacOS 10.14.3 version and updates as of the time of this post. To clarify, I did NOT have this issue when viewing the same content in Chrome or Firefox - definitely a Safari only issue.

I am creating this post as I wanted to share the solution - my account was set as a non-admin (I had my wife as the admin) and I had parental controls on; incidentally, my wife was also logged into her account on the same machine.

On these forums, I had read cases where another admin or other user logged in or watching another full screen video would cause issues.

So - to try and troubleshoot all 3 issues at once, I gave myself admin access (with my wife's help), removed the parental controls on my account, logged her off and VIOLA - it instantly fixed the issue.

I also tried logging her back in and viewing a YouTube video, going back to my account to do the same and the videos played flawlessly regardless.

If I had to guess, this is some bug in Safari related to non-admin users and/or parental controls. So annoying - Apple has really let their software quality slip lately and when issues like this are discovered and reported, it takes them years to fix.

Anyway - just wanted to share as I tried everything - clearing my cache, history, force quitting Safari - nothing fixed it except restoring admin access, removing parental controls on the account, and logging my wife out as a one time thing - I honestly don't know which of these 3 things fixed the buggy behavior, but give it a shot and it should solve the problem as a work-around until Apple fixes this glitch in Safari (I call it a glitch because neither parental controls, non-admin access, nor multiple users logged in concurrently should cause YouTube videos to frequently freeze).