It may be a GPU problem.
Try a NVRAM reset:
https://support.apple.com/en-us/HT204063
If there is no change, make an appointment at an Apple store genius bar. The evaluation will be FREE.
Ciao.
It may be a GPU problem.
Try a NVRAM reset:
https://support.apple.com/en-us/HT204063
If there is no change, make an appointment at an Apple store genius bar. The evaluation will be FREE.
Ciao.
NVRAM did not help
SMC helped
Gruss Jürgen
Bunter Bildschirm auf einen MacBook Pro 17" 2010