For years, connecting to external monitors on my MBP 9,2 (10.10.4) worked just fine (except the occasional crash). Until yesterday, where I had three crashes in quick succession. Now when the display (miniDP-to-VGA) is connected, the computer won't boot. I unlock my boot volume, but the black bar only fills to about one third before stopping. When I disconnect the adapter, it boots but once I connect the display, the laptop screen goes black and audio also dies after a few moments. The computer is still running and can only be shut down by long-pressing the power button.
I am baffled, but also unsure on how to diagnose the problem. Console shows no unusual messages.
- I booted into my second OS (elementaryOS) and it reacts to connecting the adapter, but nothing shows on the other screen except occasionally a static image. This may point to a hardware issue. Not sure. When mirroring the display, something does show, although I cannot select an appropriate resolution, which may be the tv's problem.
- I reset SMC and NVRAM, to no avail
- I also fixed permissions, although I don't know how that could fix anything, and it did not
- I logged out and the same thing happens when connecting the display
- I logged in as another user. When plugging in the display, the computer freezes, but the screen does not go black
- In Safe Mode, the screen does not turn black and the computer does not halt, but nothing shows on the display, but I can access external display settings like resolution and such.