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Why is there a line on my Macbook screen?

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  • 5 min read

Your MacBook is a reliable companion for work, entertainment, and everything. However, as with any electronic device, it’s not immune to occasional glitches and issues. Vertical or horizontal lines may appear in various parts of the screen in green, purple, black, yellow, or even multiple colours. The exact colour and pattern of these lines don’t matter much. What’s crucial is that you should deal with this issue on your MacBook Pro screen lines as quickly as possible to prevent it from causing more problems.

In this article, we have discussed what causes lines on the Macbook screen and a few ways to help you fix the issue.


What causes the lines on the Macbook screen?

Below, we have mentioned the reasons that might be causing the line on your Macbook screen.

Hardware-related issues with your Mac.

  • Physical damage to the screen from accidental impacts or drops.
  • Damage to the T-con board.
  • Fan malfunctions or blocked air vents cause overheating.
  • Troubles with the motherboard or graphics card.
  • Damage to or incorrect connections of cables.

On the other hand, software-related problems that can lead to coloured lines on your Mac screen often involve.

  • Power management software.
  • Updates to graphic card drivers.
  • Conflicts between various software programs.

Also read: Why is there an orange spot on Macbook screen?


How to fix the issue?

We have explained a few methods below to help you fix the vertical or horizontal lines on your Macbook screen.

Restart your Mac

Begin by restarting your MacBook. This simple step can often resolve software-related glitches causing the lines.


Let your Mac cool down

Overheating is a frequent cause of lines on the screen. This can happen due to hot weather, demanding tasks like video editing, or when your Mac runs multiple apps simultaneously. Ideally, you want to keep the temperature between 100°F and 192°F to ensure your Mac stays healthy. Overheating is a serious concern because it can harm your Mac’s delicate hardware.

If the place where you’re using your Mac is very hot or if you notice the Mac’s fans working hard, turn it off and wait for it to cool down before turning it on again.


Run the maintenance scripts

Usually, your Mac runs maintenance scripts to tidy up system logs and temporary files. But sometimes, these scripts don’t run as often as they should. If your screen has lines because of a software issue, running these scripts manually might help fix it.

You can use third-party apps like CleanMyMac X to run maintenance scripts on your Macbook. It comes with various tools to help keep your Mac clean, and one of them is a special module just for maintenance.


Check the display connection

If you use an external display and the lines show up on that display. Make sure the cable is properly connected at both ends. If you have another cable available, you can also test it, as a faulty cable might be the reason for this issue.

Also read: How to disable mouse acceleration on Mac?


Try a different display

If you have a spare monitor, connect it to your computer instead of the one you’re currently using. You can also try plugging it into a different port, like switching from DisplayPort to HDMI.

But if you’re not using an extra monitor and the issue is with your computer’s screen, connect it to an external monitor. If the problem continues on the external monitor, your computer’s screen is fine. However, if the issue disappears on the external monitor, it indicates a hardware problem that requires a tech expert to repair.


Reset the SMC

When you turn it on, the system management controller (SMC) is like a power manager for your Mac. If the lines on your Mac’s screen are due to a power problem, resetting the SMC might fix it.

For those using Apple Silicon Macs, a simple restart would reset the SMC on your Mac. That’s because these new Mac models no longer have the system management controller, as it is all embedded in the M1 processor.

Reset the SMC in a Mac with the T2 chip

Step 1: Shut down your Mac

Step 2: Press and hold the right Shift key + left Control key + left Option key for about seven seconds and hold the Power button.

Step 3: Keep holding all four keys for another seven seconds. If your Mac is turned on, it will turn off on its own while you are holding these keys.

Step 4: Release all the keys, wait for a few seconds, and press the Power button to turn on your Mac.

Reset the SMC in an Intel Mac with a removable battery

Step 1: Shut down your Mac and remove the battery.

Step 2: Hold the Power button for about five seconds.

Step 3: Reconnect the battery and turn on your Mac. 

Reset the SMC in an Intel Mac with a non-removable battery

Step 1: Shut down your Mac.

Step 2: Press the Shift + Control + Option keys on the left side of the keyboard. While holding these keys, press the Power button and hold them all for 10 seconds.

Step 3: Release the keys and press the Power button to turn on your Mac.

Also read: MacBook Pro trackpad not clicking: Quick Fix

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Akash Singh

Akash is a law graduate who likes to go for bike rides on the weekends soul-searching for answers to his many existential questions. You can contact him here: [email protected]

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