Water on Mac Sleep Light Blinking Continuously

Rarely, a Mac may encounter some peculiar issue during system boot that can cause quite a bit of panic, like booting to a completely black screen. It would be easy to interpret that as a potential hardware problem, and in some particularly rare situations that may be the case, but it's more often a software issue that can be resolved with some simple troubleshooting steps.

Case in point; one of our readers experience with his MacBook Pro, which out of the blue rebooted to a completely dark screen. Though it's rare, we figured this would be a good opportunity to share three potential solutions to this problem, and similar issues, should you encounter a dark screen on system start.

First, Reset the System Management Controller to Fix the Black Display on Boot

The first thing you'll want to do resolve nearly every power related issue on a Mac is to reset the SMC, or System Management Controller. This will dump and reset settings for anything power management related, and is long known to resolve problems with things like fans, heat, sleeping problems, and of course, display issues.

On any modern MacBook Pro or MacBook Air with a built-in battery, which is just a bout all of them nowadays, this is how you do that:

1. Shut down the Mac and connect it to your MagSafe adapter and a wall outlet as usual
2. Hold down the Shift+Control+Option+Power button at the same time for a few seconds
3. Release all keys at the same time, then boot the Mac as usual

Older Macs can find directions here for the same process on their machines, it's slightly different if you can take out the battery.

When the Mac boots, hopefully the black screen has gone away and you're back to normal, but if it doesn't… reader Nathan D. wrote in with the next tip.

Second, Try a Keypress Sequence to Ditch the Black Screen

Regular readers may recall that we covered some OS X keyboard shortcuts for the Shutdown, Sleep, and Restart controls of just about every Mac, and this little key press sequence takes advantage of those. Oddly enough, it seems to work to resolve some of the mystery Mac booting into black screen issues. Here's the precise sequence to follow:

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

This key press solution was discovered by reader Nathan D., who found it tucked away on MacRumors Forums, and it has worked for several other commenters there as well. Some other users on the MR forums suggest that resetting PRAM helped them too, but most power issues are resolved by the SMC reset.

Try a PRAM Reset to Resolve the Black Boot Display

If the above two tricks failed, a PRAM reset can often do the trick, as many of the commenters on this article can attest to. As a potential solution to the black screen on boot, this is done upon restarting the Mac similar to an SMC reset:

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

At this point your Mac should boot again as usual and no longer have the black display, loading Mac OS or Mac OS X as usual.

Finally; Enter Password, Hit Return

Some users in our comments report an interesting alternative finding if they hit the black screen on boot; if they enter their regular login password and hit the Enter/Return key, the Mac boots up as usual and they're good to go. Try this out, it might work for you:

1. When the Mac boots into the black screen, enter the password you'd use to login to the Mac as usual
2. Hit the Return key

If this works, you'll know rather quickly because the black screen will give way to the regular Mac OS desktop.

Turn Off Automatic Graphics Switching (for black screens on dual-GPU MacBook Pro only)

Some MacBook Pro models have dual graphics cards that switch automatically. For whatever reason those models can sometimes boot directly to a black screen. Often this can be remedied by simply disabling automatic graphics card (GPU) switching on MacBook Pro as instructed here:

1. From the  Apple menu choose "System Preferences" then go to "Energy Saver"
2. Toggle the switch next to 'Automatic Graphics Switching' to turn that off



3. Restart the Mac as usual

Did one of these solutions work to get past the black screen on Mac boot for you? If you happen to run into this unusual issue with your Mac, let us know how you resolved it by leaving a comment below, and if the above tips worked for resolving the boot to black screen problem on your MacBook, MacBook Pro, MacBook Air, and whichever Pro or Air model it may be. And of course if you have your own solution to the booting to a black screen issue, share that below in the comments as well!

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Source: https://osxdaily.com/2014/11/22/fix-macbook-pro-booting-black-screen/

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