Hi there, Probably as many this is kind of my last resort for figuring out this strange problem with my mac. Model: Macbook Pro (Retina, Mid 2012) OS X Yosemite Processor: 2,6 GHz Intel Core i7 Memory 16 GB 1600 MHz DDR3 Startup Disk Macintosh HD Graphics Intel HD Graphics 4000 1024 MB This is how my problem begun: After connecting my Mac to my Samsung Smart TV through a HDMI Cable I watched a movie on the TV. When I was done I disconnected the HDMI Cable and the computer went back to his original settings of displaying and behaved normally. After I rebooted, the Mac started normally (intro sound, little fan noise and working caps-lock), however the display screen gave no image, except in the beginning the apple logo, but now it even doesn’t do that anymore. I thought my screen was broken. Then I worked my way back through the process and connected the HDMI cable and still got no display on either the External or the Internal display. So I closed my Mac and opened it again while pulling out the HDMI Cable at the same time and the screen got back to life. Only the cable isn’t enough; it must be connected to the TV for this ‘trick’ to work. After rebooting I have to repeat this procedure. When it is connected to the TV the TV says it’s connected but gets no signal and my Mac doesn’t recognize anything, even when I hit the Detect displays button in System Preference/Displays. It seems like my screen gets stuck between the Internal and External display, but I have no idea why. Things I’ve tried: Resetting SMC and PRAM Rebooting in SafeMode Trying different screen resolutions I hope somebody can help, I can’t find similar problems on the Internet. The solutions now would be to bring a TV and a HDMI cable all the time to regain access to my screen; this is not a really good solution I guess... Thanks!