Video screen goes diagonal when enlarged to full screen

Delete com.apple.Safari.plist file and test.

Backup your Mac.

Empty the Trash.

Quit all applications.

Hold the option key down and click the "Go" menu in the Finder menu bar.

Select "Library" from the drop down.

Library > Preferences > com.apple.Safari.plist

Right click on it and select "Move it to Trash".

Restart and relaunch Safari holding the shift key down.

If this doesn’t help, “Put Back” the com.apple.Safari.plist

Right click on the Trash icon in the Dock and select “Open”.

Right click on the com.apple.Safari.plist and select “Put Back”.

Select ”Replace” from the dialog when it appears.

Uninstall Flash Player and test. https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-mac-os.html

Reset NVRAM. https://support.apple.com/en-us/HT204063

Mine has the same issue using Chrome and Safari, but it works in Firefox, thank goodness! Give it a try for those pesky videos.

I haven't seen anyone post a fix yet. One thing you can try is to go to Safari/Preferences/Websites, disable all your plugins, and test.

Maybe annoying, but less so than a diagonal screen, turn on subtitles. Seems to of fixed it for me.

Have you tried changing the screen resolution?

When entering full screen in safari video distorts

reseting the NVRAM worked great, thank you 🙂

Seems it may be a bug.

Send Apple feedback. They won't answer, but at least will know there is a problem or a suggestion for change. If enough people send feedback, it may get the problem/suggested change solved sooner.

Click here to send Feedback

I’m having this same issue and tried all of these steps as well with no luck.

Me too it's super annoying and also my screen turns green sometimes plz help

seems there is still no fix to this. I am having the same issue. anyone have any other suggestions?