Mac Pro (late 2013) shows purple startup screen
I've recently installed a new Mac Pro (late 2013) with El Capitan.
Afterwards I wanted to install Windows 10.
The latter did not work because of an error, so I restarted the mac.
Now the first screen I see when I start up the mac is 'windows purple' with a white apple icon (see photo, the white thing in the corner is a reflection)
After the bar goes to about halfway the screen reverts to the normal black again.
So far I have:
- Erased the SSD and reinstalled the system from a USB drive (clean install)
- Reset PRAM
- Used Onyx to clean up caches
However, the first thing I see when I switch on the mac is the purple screen.
Can a windows install have messed with the boot rom of my Mac!?
How can I revert the firmware (which i assume is where the problem is at) to the factory version?
Or the general question: How do i get rid of this (quite ugly, but that's beside the point) screen and get back to the normal black screen?
