Macbook screen turning black while using.

Opening and closing the lid could conceivably be restarting your Mac, so that is not a sufficient test by itself.

To separate out whether your Mac has crashed or merely blanked the display, the first step is whether the caps light can be turned on and off normally after the display goes dark.

What screensaver are you using? could you have accidentally invoked your screensaver, such as straying not the designated HotCorner?

the only 'status lights' we have on these Macs are CapsLock indicator.

when the display goes dark, can the caps lock indicator turn on and off as expected?

This indicates the Mac has not crashed, but is till running.

then your sounds like a Display hardware problem.

Genius Bar technicians are NOT trained to read panic reports and computer logs. When you present your computer at the Genius Bar with the expectation of a quote to repair it, you must generally meet these criteria:

• your Mac won't do anything

• your Mac fails diagnostics

• your Mac has a problem you can repeatably demonstrate on demand

one other oddball case:

• Apple online support has DIRECTED a Service Provider to replace specific components inside your Mac, such as the mainboard or display. Bring proof, such as case number.

They CAN run their diagnostics, which are a bit more comprehensive that the User diagnostics. In the very small amount of time they are run, “No faults detected” still does not mean “All is Well” but at least there are no detected GROSS problems.

ANY other visit to the genius bar can be an exercise in futility, because technicians are not trained to read panic reports and computer logs. If your issue is illustrated in panic reports and logs, you need an Apple Support Specialist to read your reports, determine what is causing the Hardware problem, and DIRECT a Service Provider what they should change.

I can be in the middle of typing (example: when I was typing this topic the screen turned black). I can be reading and the screen turns black. The light will turn on when the caps lock is turned on, so I still have power. Also when I shut & open the lid on my Mac the page I was on is still present. So I don’t believe that it is restarting.

The caps lock light will go on, but I still need to know why the screen suddenly goes black. As I'd mentioned I can close the lid on my Mac and open it back up and my screen is restored.

Thank you for the information. There is no genius bar nearby. The closest one is 200 miles away. I do have a local Apple tech support that I will contact.