Q: My macbook 12inch fails to boot when external monitor is attached

I have a strange problem. I have a macbook 12 inch, 2016 with OSX 10.11.4 installed.

My computer doesn't boot successfully when the external monitor is attached.

I'm using the mutiport adapter, and when the monitor is attached through the HDMI cable (even if the monitor is off), boot will end up with a black screen.

At the final state, the computer responds to the keyboard. Hitting most keys results in a "bump" sound. Caps lock seems to work, but not much else.

I tried to boot with verbose on, but the black screen state occurs after all the text scrolled by.

When the HDMI cable is not connected, the computer boots succesfully.

Here is log, just before the next reboot:

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03/05/16 11:04:33,624 WindowServer[174]: Display 0x003f003d: GL mask 0x2; bounds (2305, 0)[1 x 1], 1 modes available

off-line, enabled, Vendor ffffffff, Model ffffffff, S/N ffffffff, Unit 1, Rotation 0

UUID 0xffffffffffffffffffffffffffffffff, ColorSpace { -206507792 }

03/05/16 11:04:33,625 WindowServer[174]: MPAccessSurfaceForDisplayDevice: Set up page flip mode on display 0x042809c0 device: 0x7feeda505150  isBackBuffered: 1 numComp: 3 numDisp: 3

03/05/16 11:04:33,656 com.apple.AmbientDisplayAgent[213]: Read hardware overrides for display 0x42809c0

03/05/16 11:04:35,426 WindowServer[174]: **DMPROXY** (2) Found `/System/Library/CoreServices/DMProxy'. Run with arg = -discovery

03/05/16 11:04:35,427 WindowServer[174]: **DMPROXY** (2) Found `/System/Library/CoreServices/DMProxy'. Run with arg = -AMBDprefs

03/05/16 11:04:35,468 WindowServer[174]: CGXSetDisplayColorProfileAndTransfer: Display 0x042809c0: Unit 0; ColorProfile { 1718932604 }; TransferFormula (1.000000, 1.000000, 1.000000)

03/05/16 11:04:35,625 WindowServer[174]: **DMPROXY** (2) Found `/System/Library/CoreServices/DMProxy'. Run with arg = -discovery

03/05/16 11:04:35,626 WindowServer[174]: **DMPROXY** (2) Found `/System/Library/CoreServices/DMProxy'. Run with arg = -AMBDprefs

03/05/16 11:04:35,666 WindowServer[174]: CGXSetDisplayColorProfileAndTransfer: Display 0x042809c0: Unit 0; ColorProfile { 1718932604 }; TransferFormula (1.000000, 1.000000, 1.000000)

03/05/16 11:04:42,000 kernel[0]: IO80211AWDLPeerManager::setAwdlOperatingMode Setting the AWDL operation mode from AUTO to SUSPENDED

03/05/16 11:04:42,000 kernel[0]: IO80211AWDLPeerManager::setAwdlSuspendedMode() Suspending AWDL, enterQuietMode(true)

03/05/16 11:04:43,510 sandboxd[137]: ([249]) systemsoundserve(249) deny file-read-data /private/var/root/Library/Preferences/.GlobalPreferences.plist

03/05/16 11:04:44,000 kernel[0]: Sound assertion in AppleHDAController at line 6018

03/05/16 11:04:44,000 kernel[0]: Sound assertion in AppleHDAController at line 6019

03/05/16 11:04:44,000 kernel[0]: Sound assertion in IOHDACodecDevice at line 145

03/05/16 11:04:44,000 kernel[0]: Sound assertion in AppleHDAController at line 9949

03/05/16 11:04:45,000 kernel[0]: Setting BTCoex Config: enable_2G:1, profile_2g:0, enable_5G:1, profile_5G:0

03/05/16 11:04:46,000 kernel[0]: IO80211AWDLPeerManager::setAwdlOperatingMode Setting the AWDL operation mode from SUSPENDED to AUTO

03/05/16 11:04:46,000 kernel[0]: IO80211AWDLPeerManager::setAwdlAutoMode Resuming AWDL

03/05/16 11:04:49,000 kernel[0]: AppleCamIn::systemWakeCall - messageType = 0xE0000340

03/05/16 11:04:50,000 kernel[0]: Setting BTCoex Config: enable_2G:1, profile_2g:0, enable_5G:1, profile_5G:0

03/05/16 11:04:50,000 kernel[0]: AppleCamIn::systemWakeCall - messageType = 0xE0000340

03/05/16 11:04:50,450 WindowServer[174]: device_generate_desktop_screenshot: authw 0x0(0), shield 0x0(0)

03/05/16 11:04:50,467 WindowServer[174]: device_generate_lock_screen_screenshot: authw 0x0(0)[inf, inf, 0, 0] shield 0x0(0), dev [1280,800]

03/05/16 11:04:52,000 kernel[0]: AppleCamIn::systemWakeCall - messageType = 0xE0000340

03/05/16 11:04:52,744 com.apple.xpc.launchd[1]: (com.apple.appkit.xpc.sandboxedServiceRunner) The JoinExistingSession key is only available to Application services.

03/05/16 11:04:52,751 com.apple.xpc.launchd[1]: (com.apple.FileSyncAgent.PHD.isRunning) The HideUntilCheckIn property is an architectural performance issue. Please transition away from it.

03/05/16 11:04:52,764 com.apple.xpc.launchd[1]: (com.apple.speech.speechsynthesisd) This key does not do anything: OnDemand

03/05/16 11:04:52,764 com.apple.xpc.launchd[1]: (com.apple.trustd.agent) This key does not do anything: OnDemand

03/05/16 11:04:52,764 com.apple.xpc.launchd[1]: (com.apple.trustd.agent) The ServiceIPC key is no longer respected. Please remove it.

03/05/16 11:04:52,764 com.apple.xpc.launchd[1]: (com.apple.TrustEvaluationAgent) This key does not do anything: OnDemand

03/05/16 11:04:53,000 kernel[0]: AppleCamIn::systemWakeCall - messageType = 0xE0000340

03/05/16 11:04:53,000 kernel[0]: en0: BSSID changed to bc:67:1c:f9:03:8f

03/05/16 11:04:53,000 kernel[0]: en0: channel changed to 36

03/05/16 11:04:53,209 WindowServer[174]: CGXDisplayDidWakeNotification [47282098248]: posting kCGSDisplayDidWake

03/05/16 11:04:53,211 WindowServer[174]: handle_will_sleep_auth_and_shield_windows: Deferring.

03/05/16 11:04:53,000 kernel[0]: Sound assertion in AppleHDAController at line 8718

03/05/16 11:04:53,349 softwareupdated[265]: BUG in libdispatch client: kevent[EVFILT_VNODE] add: "Bad file descriptor" - 0x9

03/05/16 11:05:08,094 launchd[1]: BUG in libdispatch: 15E2066 - 1718 - 0x0

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