Black Login Screen

Now running 10.11.1 and still the same issue.

Hi Mike,

This issue has a couple of potential causes:

First try an SMC reset (this won't affect anything else on your iMac)

1. Shut down the computer.
2. Unplug the power cord.
3. Wait fifteen seconds.
4. Attach the power cord.
5. Wait five seconds, then press the power button to turn on the computer.

Then if that doesn't fix it, follow these steps while at the black login screen (i.e. instead of logging in):

1. Press the Power / OFF button once – this will bring up the dialog box which you can’t see
2. Press the “S” button – this is the shortcut to sleep the Mac
3. Hold down the Power button until a hard shut down is forced
4. Wait about 15 seconds, then hit the Power button again to turn it back on

If the above two tricks failed, an NVRAM reset is what is required.

1. Reboot the Mac and as soon as you hear the boot chime, hold down the Command+Option+P+R keys together
2. When you hear the boot sound again, the PRAM has been reset so let the Mac boot again as usual

Please let us know which of these answers resolved the issue for you.

-Max

Tried all 3 and no go. Same thing.

Strange. With the second one, you may have to adjst the first step if simply pressing the power button on you iMac doesn't bring up the Shutdown/Restart/Sleep dialog box - perhaps you have to hold it for a bit or something - and adjust step 1 accordingly. You'd have to experiment to see what brings up that dialog box for you when you can see the screen obviously.

New clue/data. I have a 27 inch Thunderbolt Display attached to it. When I unhook it and boot I see the lock screen! Maybe a bug with the Thunderbolt Display and 10.11??

That sounds even more like SMC now as that is directly responsible for external monitors. Going back to my first post, did you disconnect the power cord from the socket or the iMac? It's the iMac you need to remove it from. Also, try waiting more than 15 seconds - something like 20.

Finally, do you have AirParrot or Elitma SyncMate (or any other software with 3rd party kernel extensions that interact with display kexts) installed on your system?

Ok so I also have a Dell 27 inch monitor siting in a closet that hooks up via display port. I hooked that one up and took the TB display out. Same problem. Black Screen for the lock screen. Yes I did the first one and waited 20 seconds. I can do it again. But it seems not to like dual monitors on the lock screen.

Also to add to your second question I saw the posts on the Kexts stuff when I first ran into this earlier today and I have unloaded all of them so I have none now. Still have the issue.

Lots of people have your setup though, and you're the first to report this here, so I think there must be something about your system.

Unloading them only stops them until the next reboot. To see which are currently active on your system, please post the output of:

kextstat | grep -v com.apple

Obviously you'll need to run that before unloading any kexts.

Sorry I deleted the files and when I run the above command nothing shows up. So no kexts.

I am now leaving the iMac unplugged for a few miniutes.

No change. Left it unplugged for a few minutes and still black lock screen. I am going with a bug here and I hope it can be fixed soon!

Yes, even though it may only affect a minority of people with a certain system and external monitor setup, it is still a bug so it would be good to report it either via the Feedback Assistant app or from https://bugreport.apple.com

Max

Just entered it. I hope it is fixed soon!!

There's also a chance that you missed a kext - if you post the output of the following, I'll look over it as a second pair of eyes:

ls -1 /Library/Extensions/ ; ls -1 /Library/Application\ Support/VirtualBox/ ; ls -1 /Library/Application\ Support/EltimaSyncMate/ ; ls -1 /System/Library/Extensions/

I think if it was one it would affect more than just the lock screen. But here is the list have at it.

ALF.kext

AMD2400Controller.kext

AMD2600Controller.kext

AMD3800Controller.kext

AMD4600Controller.kext

AMD4800Controller.kext

AMD5000Controller.kext

AMD6000Controller.kext

AMD7000Controller.kext

AMD8000Controller.kext

AMD9000Controller.kext

AMDFramebuffer.kext

AMDMTLBronzeDriver.bundle

AMDRadeonVADriver.bundle

AMDRadeonX3000.kext

AMDRadeonX3000GLDriver.bundle

AMDRadeonX4000.kext

AMDRadeonX4000GLDriver.bundle

AMDShared.bundle

AMDSupport.kext

ATIRadeonX2000.kext

ATIRadeonX2000GA.plugin

ATIRadeonX2000GLDriver.bundle

ATIRadeonX2000VADriver.bundle

Apple16X50Serial.kext

AppleACPIPlatform.kext

AppleAHCIPort.kext

AppleAPIC.kext

AppleBMC.kext

AppleBacklight.kext

AppleBacklightExpert.kext

AppleBluetoothMultitouch.kext

AppleBluetoothRemote.kext

AppleCameraInterface.kext

AppleCredentialManager.kext

AppleEFIRuntime.kext

AppleFDEKeyStore.kext

AppleFIVRDriver.kext

AppleFSCompressionTypeDataless.kext

AppleFSCompressionTypeZlib.kext

AppleFWAudio.kext

AppleFileSystemDriver.kext

AppleGraphicsControl.kext

AppleGraphicsPowerManagement.kext

AppleHDA.kext

AppleHIDKeyboard.kext

AppleHIDMouse.kext

AppleHIDTransport.kext

AppleHPET.kext

AppleHPM.kext

AppleHSSPIHIDDriver.kext

AppleHSSPISupport.kext

AppleHV.kext

AppleHWSensor.kext

AppleIRController.kext

AppleInputDeviceSupport.kext

AppleIntelBDWGraphics.kext

AppleIntelBDWGraphicsFramebuffer.kext

AppleIntelBDWGraphicsGLDriver.bundle

AppleIntelBDWGraphicsMTLDriver.bundle

AppleIntelBDWGraphicsVADriver.bundle

AppleIntelBDWGraphicsVAME.bundle

AppleIntelCPUPowerManagement.kext

AppleIntelCPUPowerManagementClient.kext

AppleIntelFramebufferAzul.kext

AppleIntelFramebufferCapri.kext

AppleIntelGraphicsShared.bundle

AppleIntelHD3000Graphics.kext

AppleIntelHD3000GraphicsGA.plugin

AppleIntelHD3000GraphicsGLDriver.bundle

AppleIntelHD3000GraphicsVADriver.bundle

AppleIntelHD4000Graphics.kext

AppleIntelHD4000GraphicsGLDriver.bundle

AppleIntelHD4000GraphicsMTLDriver.bundle

AppleIntelHD4000GraphicsVADriver.bundle

AppleIntelHD5000Graphics.kext

AppleIntelHD5000GraphicsGLDriver.bundle

AppleIntelHD5000GraphicsMTLDriver.bundle

AppleIntelHD5000GraphicsVADriver.bundle

AppleIntelHDGraphics.kext

AppleIntelHDGraphicsFB.kext

AppleIntelHDGraphicsGA.plugin

AppleIntelHDGraphicsGLDriver.bundle

AppleIntelHDGraphicsVADriver.bundle

AppleIntelHSWVA.bundle

AppleIntelIVBVA.bundle

AppleIntelLpssDmac.kext

AppleIntelLpssGspi.kext

AppleIntelLpssI2C.kext

AppleIntelLpssI2CController.kext

AppleIntelLpssSpiController.kext

AppleIntelLpssUART.kext

AppleIntelMCEReporter.kext

AppleIntelPCHPMC.kext

AppleIntelSNBGraphicsFB.kext

AppleIntelSNBVA.bundle

AppleIntelSlowAdaptiveClocking.kext

AppleKextExcludeList.kext

AppleKeyStore.kext

AppleKeyswitch.kext

AppleLPC.kext

AppleLSIFusionMPT.kext

AppleMCCSControl.kext

AppleMCP89RootPortPM.kext

AppleMIDIBluetoothDriver.plugin

AppleMIDIFWDriver.plugin

AppleMIDIIACDriver.plugin

AppleMIDIRTPDriver.plugin

AppleMIDIUSBDriver.plugin

AppleMatch.kext

AppleMikeyHIDDriver.kext

AppleMobileFileIntegrity.kext

AppleMultitouchDriver.kext

AppleOSXUSBNCM.kext

AppleOSXWatchdog.kext

ApplePlatformEnabler.kext

AppleRAID.kext

AppleRAIDCard.kext

AppleRTC.kext

AppleSDXC.kext

AppleSEP.kext

AppleSMBIOS.kext

AppleSMBusController.kext

AppleSMBusPCI.kext

AppleSMC.kext

AppleSMCLMU.kext

AppleSRP.kext

AppleSmartBatteryManager.kext

AppleStorageDrivers.kext

AppleThunderboltDPAdapters.kext

AppleThunderboltEDMService.kext

AppleThunderboltIP.kext

AppleThunderboltNHI.kext

AppleThunderboltPCIAdapters.kext

AppleThunderboltUTDM.kext

AppleTopCase.kext

AppleTyMCEDriver.kext

AppleUSBACM.kext

AppleUSBAudio.kext

AppleUSBCDC.kext

AppleUSBDMM.kext

AppleUSBDisplays.kext

AppleUSBECM.kext

AppleUSBEEM.kext

AppleUSBEthernet.kext

AppleUSBEthernetHost.kext

AppleUSBFTDI.kext

AppleUSBMultitouch.kext

AppleUSBNCM.kext

AppleUSBNetworking.kext

AppleUSBTopCase.kext

AppleUSBWCM.kext

AppleUpstreamUserClient.kext

AppleVADriver.bundle

AppleWWANAutoEject.kext

AppleXsanScheme.kext

Apple_iSight.kext

AudioAUUC.kext

BootCache.kext

CellPhoneHelper.kext

CoreCaptureResponder.kext

CoreStorage.kext

DSACL.ppp

DSAuth.ppp

DVFamily.bundle

Dont Steal Mac OS X.kext

EAP-KRB.ppp

EAP-RSA.ppp

EAP-TLS.ppp

GeForce.kext

GeForceAIRPlugin.bundle

GeForceGA.plugin

GeForceGLDriver.bundle

GeForceMTLDriver.bundle

GeForceTesla.kext

GeForceTeslaGLDriver.bundle

GeForceTeslaVADriver.bundle

GeForceVADriver.bundle

IO80211Family.kext

IOACPIFamily.kext

IOAHCIFamily.kext

IOATAFamily.kext

IOAVBFamily.kext

IOAccelerator2D.plugin

IOAcceleratorFamily.kext

IOAcceleratorFamily2.kext

IOAudioFamily.kext

IOBDStorageFamily.kext

IOBluetoothFamily.kext

IOBluetoothHIDDriver.kext

IOCDStorageFamily.kext

IODVDStorageFamily.kext

IOFireWireAVC.kext

IOFireWireFamily.kext

IOFireWireIP.kext

IOFireWireSBP2.kext

IOFireWireSerialBusProtocolTransport.kext

IOGraphicsFamily.kext

IOHDIXController.kext

IOHIDFamily.kext

IONDRVSupport.kext

IONVMeFamily.kext

IONetworkingFamily.kext

IOPCIFamily.kext

IOPlatformPluginFamily.kext

IOReportFamily.kext

IOSCSIArchitectureModelFamily.kext

IOSCSIParallelFamily.kext

IOSMBusFamily.kext

IOSerialFamily.kext

IOSlowAdaptiveClockingFamily.kext

IOStorageFamily.kext

IOStreamFamily.kext

IOSurface.kext

IOThunderboltFamily.kext

IOTimeSyncFamily.kext

IOUSBAttachedSCSI.kext

IOUSBFamily.kext

IOUSBHostFamily.kext

IOUSBMassStorageClass.kext

IOUSBMassStorageDriver.kext

IOUserEthernet.kext

IOVideoFamily.kext

L2TP.ppp

Libm.kext

NVDAGF100Hal.kext

NVDAGK100Hal.kext

NVDANV50HalTesla.kext

NVDAResman.kext

NVDAResmanTesla.kext

NVDAStartup.kext

NVMeSMARTLib.plugin

NVSMU.kext

OSvKernDSPLib.kext

PPP.kext

PPPSerial.ppp

PPPoE.ppp

PPTP.ppp

Quarantine.kext

Radius.ppp

SMARTLib.plugin

SMCMotionSensor.kext

Sandbox.kext

System.kext

TMSafetyNet.kext

acfs.kext

acfsctl.kext

autofs.kext

cd9660.kext

cddafs.kext

corecapture.kext

corecrypto.kext

exfat.kext

iPodDriver.kext

mcxalr.kext

msdosfs.kext

ntfs.kext

pmtelemetry.kext

pthread.kext

smbfs.kext

triggers.kext

udf.kext

vecLib.kext

webcontentfilter.kext

webdav_fs.kext

/System/Library/Extensions/ is all clear, but you didn't post the output of:

ls -1 /Library/Extensions/ ; ls -1 /Library/Application\ Support/VirtualBox/ ; ls -1 /Library/Application\ Support/EltimaSyncMate/ ;

DroboTBT.kext

TrustedDataSCSIDriver.kext

ls: /Library/Application Support/VirtualBox/: No such file or directory

ls: /Library/Application Support/EltimaSyncMate/: No such file or directory

I also had the Drobo and SCSIDriver removed. Still had the issue so I reinstalled my Drobo software.

Fair enough. There should be more in your /Library/Extensions/ folder normally - the default OS X installation puts the following kexts in there:

ACS6x.kext

APExtFramebuffer.kext

ATTOCelerityFC8.kext

ATTOExpressSASHBA2.kext

ATTOExpressSASRAID2.kext

ArcMSR.kext

CalDigitHDProDrv.kext

HighPointIOP.kext

HighPointRR.kext

PromiseSTEX.kext

SoftRAID.kext

Anyway, I'm won over, I reckon now that the bug is intrinsic to OS X 10.11 and hopefully your bug report will help get it resolved.