Q: External monitor OS bug - Black Screen with cursor

I have this same issue on my Mac Book Pro Retina 15" (Late 2012). No problems with Yosemite--problem started since El Capitan installed. I tried every trick in the book to get this to work (I use 2 external monitors.. Thunderbolt to HDMI and HDMI).. Tech support seems to have never heard of this and is dumbfounded. Any ideas are welcome.

Thanks!

I have the same problem. Both monitors (Retina Mac + external LG) are black at logon. The only thing I see is the mouse pointer.

I try to click at the area where my logon-icon usually was and enter my PWD, and then I can logon and my desktop appears on both screens. Until the next reboot

But that's not the solution at all...

I just experienced the exact same issue. I called Apple Support and the issue was fixed by plugging my computer to the charger.  I was shocked to hear that as well.  Apparently, in order for this feature to work you have to have the following 3 things:

1) An external mouse/keyboard connected to the Macbook

2) An adapter connected to the external monitor that is configured for "Mirror" arrangement

3) Macbook must be plugged in to the charger

I had the top 2 items and the symptoms were identical.   As soon as I would try to use the external monitor alone, I would get a black screen with just a mouse pointer and nothing else.  Once I plugged the laptop into the charger, everything worked fine.  My Macbook is closed right now and I'm connected to my external monitor and everything seems to be working. I'm using El Capitan as well.  Hope this helps.

Hi guys,

I seem to have exactly the same issue. I am on Mac Pro (late 2013) and just recently updated to El Capitan. I can confirm that I have never had something like that happening on Yosemite, but here - I can no longer have a proper boot. Every time when I restart the computer - I get to this black screen. So all I can do is just trying to login blindly. The combination that works sometimes is hitting the first letter of my username, then hit enter and then put the password. At some point that works eventually and I am able to continue normally using the computer. It doesn't happen when I wake it from sleep, but only after restart. I have a secondary monitor connected via HDMI (well it's a Cintiq HD tablet actually, but still as far as OS is aware - its yet another monitor). I haven't trying reaching out to Apple support yet, but I also found other topics of other people complaining of similar issue.

I did apply the recent update, but that didn't work either...

Same issue here. Brand new iMac 5k out of the box. At one point, it was booting up to black screen (with curser) regardless of what was plugged in, so I figured out Apple's Safe Mode (hold shift while booting).

Same problem here.

Late 2015 27" 5K iMac El Capitan 10.11.1

Did you try booting in Safe Mode?

Hold down Shift immediately after pressing power and release after you see the grey Apple logo. Then try rebooting normally and see if the problem went away.

Hi Nic - Paul from UK, exactly the problem you describe - very annoying!! I have the following:

iMac late 2015 5k

23" Apple Display (connector mini display to DVI) connected to one of the thunderbolt ports

On boot with external connected black screen pus cursor

If I boot with the external not connected and then connect the display all seems to be fine ... but this is a pain.

Paul

It only works once, it comes back after the next reboot.  Are you even trying before you respond or are you just guessing for points?

I have the same problem. I upgraded my Macbook Pro 15 Early 2011 to Macbook Pro 15 Retina Late 2013. Both El Capitan with Dell U2713HM connected using display port. The old Macbook worked fine, but know I can see only black screen with cursor. If I disconnect the monitor and restart, it is fine. Any workaround?

Unfortunately, the only workaround is what you're already doing: unplug the 2nd monitor before El Capitan boots.

One thing I want to try to clarify. I'm using a Thunderbolt to Mini DVI adapter to connect my 2nd monitor. Is that the case with everyone else? Maybe we can isolate this issue a little more for our good buddy Apple.

My monitor is connected using DisplayPort to Mini Display Port (thunderbolt) adapter.

I have exactly the same issue. Brand new iMac 5K, connected to a 30" Apple Cinema Display with the Mini Display Port to Dual Link DVI (thunderbolt) adapter.

On start up iMac screen shows black screen with white Apple logo and quick loading bar then both screens stay black, however the mouse cursor is there and I can move it across both screens. Only solution was to unplug the Cinema Display and restart, then plug it back in after the iMac was running. What a pain... 

I did find a work around! I got the idea from Sandspiel above (talking about trying to find the field for his login password), so I disabled the password on startup and tried restarting with the Cinema Display plugged in. It worked, as soon as the computer started up both screens came on simultaneously! 

Turning off login password-

http://www.howtogeek.com/202411/how-to-login-to-os-x-yosemite-automatically-with out-a-password/

This is a workaround and not ideal for a laptop that could fall into the wrong hands. My iMac is a bit safer in my home, but it is still a huge problem and I am hoping someone figures it out...

Same problem