OS X Login screen mirrored

[ericsvizeny]

My iMac pro is booting in mirrored mode when I don't even have that selected. If I do command + F1 it shows the extended desktop mode which is how it should be but this is only a temporary fix. I'm using a thunderbolt 3 to HDMI adapter for my 1080p television. I have reset PRAM and SMC to no avail. As well as fiddling around with the display settings. I also have tried disk repair and different orientations for the dual monitor setup. No luck. I had an iMac pro with the same exact set up and cables working not even a few weeks ago. Any ideas?

 

[ericsvizeny]

Bump

 

[mikehalloran]

You don’t have mirroring checked?

https://support.apple.com/en-us/HT202351

If you hit the Option key in Display Settings, you’ll see other choices.

 

[ericsvizeny]

You don’t have mirroring checked?

https://support.apple.com/en-us/HT202351

If you hit the Option key in Display Settings, you’ll see other choices.

Mirroring is unchecked. When I hold down option key I only get the option to detect displays..

 

[ericsvizeny]

I tried a different screen and hdmi cable just a standard 23" asus monitor and the issue went away and works as it should. Troubleshooted with another Vizio 47" 1080p tv and the issue is still there. So it's not the adapter or hdmi cable. Apples engineers just told me to update to the latest update which they released today and I still have the same issues. For some reason OS X isn't playing well with 1080p televisions. I tried factory resetting my tv, new hdmi cable, and a different hdmi port on the tv and that still did not fix the issue. Any ideas?