When connecting an external non Apple Display to my macbook air with an VGA to thunderbolt adapter the external display won't show my Desktop. Instead it will only show for a second my desktop and then go black.
My mac knows that there is a display connected as I can see from the display settings.
When not mirroring my Desktop I can actually move my windows over to the second display, but the actual display stays black, just plain black (but it is still on and active as I can see from my display status light).
I was able to reproduce and log the problem in console. The log shows following actions:
- I am logged into my account and plugin the VGA to thunderbolt adapter cable with the external display connected
- My MacBook Air notices that a second display has been plugged in and switches it's display mode.
- My external display shows for a moment my desktop and the turns black, but stays active (The external display status light indicate this to me) as if it would be still showing my desktop
I was also able to log what happened when my external display would finally start to show my desktop. If I am not mistaken I have just plugged out the VGA to thundebolt adapter and changed from mirrored display to not mirrored. This is what I have been doing afterwards:
- Plugin the VGA adapter cable with connected display
- The extended desktop shows up on external display
- Fiddling around with mirroring and not mirroring the display can sometimes solve the problem
- Pulling out the VGA to thunderbolt adapter and plugging it in again can sometimes solve the problem
- Plugging out the electricity for the external display can sometimes solve the problem
- All actions above combined in different order can sometimes solve the problem