Does Your Mac Screen Have Horizontal Lines? Here’s A Fix That Works!

One of the greatest horrors in life can be waking up one fine day to find a series of black horizontal lines painted across your Mac display. If you haven’t accidentally dropped, banged up, or caused a shock to your laptop, there are other causes that can lead to such an anomaly. However, it is reason enough to send grown-ups into a panicked frenzy thinking about the worst-case scenario of replacing the screen and the hefty price tag it comes with. 

We advise you to save the worry and anxiety after trying our quick-fix methods because there is a huge possibility the screen glitch is caused by some kind of system error. Once you try the methods mentioned below in the order as described, you’ll most likely find these lines gone for good. If not, sometimes the problem is deeper than just a glitch. We’ll talk about that after teaching you about our screen-fixing tricks. Read on to know all about it.

Why Does My Mac Have Horizontal Black Lines on The Screen?

The first cause for these lines to appear is excessive heat within the system. Maybe you run the Mac for heavy tasks and for long durations such as gaming, editing, and others. This can be termed a T-Con problem, where there is damage due to heat, or the fans failing.

Is There a Way To Avoid The Lines From Increasing?

To mitigate this issue, you can take the following steps as a preventive first-aid to your Mac:

  1. Cool your MacBook down by giving it a break or keeping it under a fan.
  2. While working on an external display, shut the MacBook screen.

How Do I Troubleshoot?

Before you take your Mac to the service store, try these methods to troubleshoot.

  1. Take a Screengrab: A screenshot will help you understand if this is a GPU malfunction or a display problem. If your lines show up in the screenshot, it is the former and if not, it is the latter issue.
  2. Reset the System Management Controller or SMC: Reset your SMC by shutting down the Mac and unplugging the power cord along with other inputs. Wait for 15 seconds before plugging the power cord back again, and restart the Mac after 5 seconds.
  3. Reset the Parameter Random-Access Memory or PRAM: Shut down your Mac and power it up again. Before the grey screen appears, hold the Command+Option+P+R keys together until your system restarts again. Release the keys after the second tone. This will get your screen back to normal but may delete your custom settings on the Mac.


You can try all of the methods mentioned above sequentially to see if the problem gets resolved. We hope our blog helped you diagnose and fix your Mac screen.

However, if these steps still don’t get rid of the black lines, you need to get your Mac device checked at an authorized Apple service center. There could be an underlying problem that certified technicians will be able to fix in no time!

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