Quicktime videos go black in full screen after 10.14.5 update

I have the exact same issue on a Mac mini 2018 running Mojave 10.14.5 (which includes iTunes 12.9.5.5): when trying to play movies full screen in iTunes, the screen will go black - unless I keep the on-screen control bar in the bottom visible or move the mouse (which amounts to the same).

I had no problem on Mojave 10.14.4 - this is a bug that was introduced in 10.14.5.

See: https://discussions.apple.com/thread/250382242

My Mac mini 2012, also on Mojave 10.14.5, does not have this problem.

There are several others with the same problem, where Mojave 10.14.5 and Mac mini are the common factors.

https://discussions.apple.com/thread/250368946

https://discussions.apple.com/thread/250376886

I tried contacting Apple Support. You can apparently not email them, but you can request them to call you via the support pages. That is what I did. I got an email from them confirming they got my support request (with ticket number). But even though their support pages state that they will call you back within 2 minutes, I am still waiting for their call now 3 hours later...

Apparently problem fixed in 10.14.6 (beta3) as well as 10.15.0 (beta4) so should be available in near future.

-- David

Hello TheiMac74,

Thanks for that info and for choosing the Apple Support Communities. If I understand correctly, you are unable to watch QuickTime videos in full screen on your Mac mini. If you haven't already, please follow the relevant steps in this Apple resource:

Get help with video issues on external displays connected to your Mac

You can figure out if unexpected behavior is related to a user file or setting by trying to reproduce the issue from another user account. This process includes creating a new user account, logging in to it, and testing for the issue.

How to test an issue in another user account on your Mac

Cheers!

Hi Mr Community specialist. This is a real bug affecting Mac Mini 2018 models. Generic trouble shooting won't make this go away. Could you please escalate this issue to an engineer to fix this? It's affect many full screen modes in multiple programs (another example: PS4 remote play). Some change in either the intel graphics driver or something else in 10.14.5 caused this.

Yep same here - Mac mini 2018, it broke in Mojave 10.14.5 (that automatically installed itself overnight I might add).

Please Apple, don't turn into Microsoft - I've had enough of their forced updates bricking an eGPU setup on my son's Windows machine. At least Microsoft let you roll back an update if it causes issues...

I've now turned off automatic updates.

This seems to be a common problem (which I've got too). There are multiple threads:

https://discussions.apple.com/thread/250368946

https://discussions.apple.com/thread/250376886

https://discussions.apple.com/thread/250382242

This happening on a Mac mini seems to be common to all of them.

I have the same problem on my MBP - https://discussions.apple.com/thread/250387292

I am positive that 10.14.5 is at fault - I tried it and updated on my second MBP and the problem occurred just after the update.

Same here . mac mini 18 running 1080p 75hz ( though this happens in default , 1600x900 60hz , 50hz etc. )

I did notice one thing if you keep the control / transport bar up by leaving your mouse / trackpad curser on it the screen will not go Black ...so this seams like a quicktime bug to me .

That sounds like good news. Although Apple didn’t seem to be in a rush to fix it.