Q: Macbook Pro: Only recognizes secondary monitor on startup

Hi,

I have brand new MacBook Pro (Retina, 15-inch, Mid 2015) running 10.10.5, connected to a secondary external monitor (Samsung S24D590). Everything is set up correctly, the external monitor set up as secondary. However, each time I boot, the laptop screen is black and inactive, while the Samsung suddenly acts as primary and only screen. The laptop monitor doesn't even appear in the display settings. Removing the HDMI cable activates the laptop monitor again, and then I can plug it back in and then set up the Samsung as secondary again. Repeat every boot. Annoying. Any solutions?

Specs MacBook:

MacBook Pro (Retina, 15-inch, Mid 2015)

OS X Yosemite 10.10.5

2,8 GHz Intel Core i7

16 GB 1600 MHz DDR3

AMD Radeon R9 M370X 2048 MB

Secondary monitor:

Samsung S24D590 connected through HDMI