Why is There A Black Line on My MacBook Screen?

Are you seeing black lines flickering across your MacBook screen? We completely understand how annoying and worrisome it can be to deal with a glitchy display, but there’s no need to panic. It doesn’t necessarily indicate severe hardware issues. There are some easy software troubleshooting steps that you can try first.

4 Reasons Why MacBook Screen Shows a Black Line

A black line on your MacBook screen usually points to four main causes: hardware damage, software glitches, connection issues, or physical impact. Common hardware problems include a faulty GPU, overheating, a damaged screen, frayed display cables, or even a failing motherboard. Software-related issues like corrupted display drivers, buggy macOS updates, or in-app errors can also interfere with display output.

In some cases, loose or damaged connectors between the screen and motherboard may be to blame. And of course, accidental drops or pressure can physically damage the display, resulting in visible black lines.

After tracing the cause, here are some troubleshooting steps that you can try:

1. Reboot Your Mac

2. Update macOS

Running an outdated macOS version might trigger several issues, like incompatibility with certain apps, unresponsive behavior, and slow performance. It may even cause the display to flicker.

1. Go to System Settings > General.
2. Click Software Update and allow the system to check for updates.
3. If a more recent software version is available, download and install it.
   

3. Check Temperature

Typically, Macs overheat because of poor room ventilation, RAM-heavy apps, and intensive CPU usage. It’s worth knowing that Macs are designed to operate within a temperature range of 50 to 95 degrees Fahrenheit (50 to 95 degrees Fahrenheit). 

There can be situations when you’re using your MacBook outdoors on a hot day, or have placed the Mac on a soft pillow. This can affect the overall performance and even trigger overheating problems. 

If you feel your Mac is warmer than usual and you’re facing display problems, try moving to a cooler area. Give it some time to rest, and it should return to its normal temperature.

NOTE

For more details, visit our guide on how to cool down your MacBook.

4. Connect an External Display

Connecting an external display to your MacBook can help isolate the issue. You can use a computer monitor, a second Mac, or even a TV and connect it with a cable or even wirelessly. 

• If the black lines appear only on your MacBook and not on the connected display, there is something wrong with your Mac’s display. In this case, move to the other steps mentioned below.
• If black screens appear on both displays, something is wrong with your GPU.

5. Check the Connection

It may sound very obvious, but be sure to check the connection between your Mac and the external monitor or any other accessory you’ve connected. Just make sure all the connections are tight and secure. Even better, disconnect and reconnect the cable firmly for a secure connection. While doing this, make sure to check the following:

• Ports and cables are intact and aren’t worn out or damaged. If the connection ports appear to be loose or the cables have any visible signs of damage, it’s time to replace them.
• The cables and adapters are in working condition.

6. Inspect Physical Damage

If there’s physical damage to your Mac’s screen, it needs to be repaired with the help of a professional.

To verify, check the following:

• Are there any cracks on the screen?
• Did your Mac suffer a harsh drop recently?

Apart from this, your MacBook might have suffered internal damage. This can happen when you apply some sort of pressure to your machine. Or, you accidentally close the lid when there was something between the screen and the keyboard. In such cases, the glass may remain intact, but the display panel gets damaged.

7. Resetting the SMC (Intel Macs Only)

The System Management Controller (SMC) on a MacBook is an important chip responsible for several internal settings, such as temperature, power consumption, display settings, and more. 

If it’s a power issue, resetting the SMC can fix the black lines problem on your Intel-powered MacBooks.For complete details, here’s our guide on how to reset SMC on a Mac.

8. Running Apple Diagnostics

Apple Diagnostics is a built-in tool to detect hardware problems on your Mac. You can run this tool to figure out whether the MacBook display issue stems from a faulty graphics processor or a damaged display. When the test finishes, it will provide a reference code indicating the problem and how to fix it.

Before running Apple Diagnostic, make sure of the following:

• Your MacBook is running the latest software version.
• Turn off your MacBook.
• Disconnect any third-party accessories except keyboard, mouse, or other essential ones.

On Apple Silicon Macs:

• Hold down the Power button. 
• Wait until your Mac turns on and you see the Startup Options screen.
• Press Command + D on your Mac’s keyboard. 

On Intel Macs:

• Turn on your Mac and immediately hold down the D key.
• Wait until you see the language option box.
• Release the D key.

If you see ADP000, nothing is wrong with the hardware. However, if you see VFD001 to VFD007, it indicates a problem with the display or the GPU.

9. Reinstall macOS

The final resort is to reinstall macOS. Doing this will wipe off complex software bugs and install the current version of the recently installed macOS. The process may seem overly complex, but it’s fairly easy to do through macOS Recovery.

On Apple Silicon Macs

1. Shut down your computer.
2. Hold the Power button until you see Loading startup options. 
3. Click Options > Continue.
4. When asked, enter your MacBook’s password and follow the on-screen instructions.

On Intel Macs

1. Shut down your computer.
2. Press the power button and then press and hold Command + R.
3. Release Command + R when you see the Apple logo or a spinning globe.

If nothing helps, you might be dealing with more complex issues like hardware failure. In such cases, the best option is to head to contact Apple Support for professional help.