How to Fix Blue Lines on Mac Screen? Here Are Effective Ways

A user on Reddit shared their frustration after noticing a persistent thin blue line on their MacBook Pro screen. According to the user, “I recently noticed a thin blue line vertically on the screen... I did all the resets again. It does not disappear though.”

If you’re seeing similar blue lines on Mac screen, don't worry! In this article, I will explain the key reasons behind this issue and share nine effective solutions to help you fix it quickly.

I'll also introduce UPDF, a powerful PDF editor that can help you handle your PDF documents more productively on Mac. You can click below to download and try it for free!

Part 1. TL;DR

Blue lines on the Mac screen can be due to a hardware or software issue. You can try these nine proven fixes to troubleshoot and resolve the problem quickly.

1. Change Computer Background
2. Calm Down Your Mac
3. Reset PRAM
4. Restart the Mac
5. Uninstall macOS Beta
6. Update to the Latest macOS
7. Run Apple Diagnostics
8. Reinstall macOS
9. Contact Support

Part 2. Why are Blue Lines on Mac Screen?

Blue lines on your Mac’s screen can be due to issues with the device’s display or software. Let me explain the specific reasons behind them:

• The internal display cable might be loose or worn.
• The display screen itself is old or damaged.
• The graphics chip or GPU might not be working properly.
• A very high Mac temperature is causing visual issues.
• There are random bugs or deeper issues with your Mac’s system.
• Mac's memory settings are corrupt or misconfigured.

Also Read: MacBook Touch Bar Not Working/Showing? 8 Effective Fixes

Part 3. How to Fix Mac Blue Lines on Screen?

You can fix blue lines on your Mac’s screen in a few easy steps. Below, I’ve explained the nine most effective solutions you can try right now.

Fix 1. Change Computer Background

The blue lines on Mac screen might just be visual artifacts triggered by certain desktop wallpapers. In this case, using a plain or default wallpaper can help remove them.

Here's what to do.

1. Right-click on the Desktop. Select “Change Wallpaper”.

• Go to “Wallpaper.” Then, select a simple image or a plain solid color.
• Click the “Download” button to get and apply the wallpaper.

Fix 2. Calm Down Your Mac

Apple recommends a temperature range of 50°F to 95°F for Mac’s optimal performance. A temperature higher than this may cause temporary display glitches.

To cool your Mac:

1. Shut down your Mac. Let it rest for 10-15 minutes.
2. Remove any case or cover to allow better airflow.
3. Use compressed air to clean the vents and remove dust that traps heat.
4. Reboot your Mac and monitor its temperature. To do this, open Terminal and type in: sudo powermetrics --samplers smc |grep -i "CPU die temperature"

Fix 3. Perform a PRAM Reset

Resetting PRAM will refresh the display settings, resolution, and any other configurations causing blue lines on Mac screen.

Here’s how to do it.

1. Shut down your Mac. Then, press the power button and quickly hold the “Option+Command + P+R” keys.
2. Keep pressing until you hear the startup sound 3 times. Then, release the keys.

Fix 4. Restart Mac

A simple restart will refresh any system glitches that might be causing Mac blue lines on screen. To restart your Mac:

1. Click the Apple logo and select “Restart.”
2. Click “Restart” again to confirm your action.

Fix 5. Uninstall macOS Beta

Beta versions are unstable and can cause random glitches, including the blue lines on Mac screen. In this case, downgrading to a stable release can resolve the issue.

Here’s what to do.

1. Restart your Mac and immediately press “Command + R” to enter Recovery Mode.
2. In the Utilities window, select “Disk Utility.” Then, erase your startup disk.

• Return to the main Utilities menu and click “Reinstall macOS” > “Continue.”

• Follow the prompts to install the latest stable version of the software.

Fix 6. Update to the Latest macOS

An outdated system can have compatibility issues with the graphics or display settings. Updating the system can help fix the issue.

1. Go to the “Apple” menu > “System Preferences”.
2. Select the “Software Update” option.

• Once an update appears, click “Upgrade Now” to install it.

Fix 7. Run Apple Diagnostics

Apple Diagnostics checks your Mac for hardware issues. These include problems with the GPU or screen, which may cause Mac blue lines on screen.

Follow these steps to run it.

For Intel-based Macs:

1. Restart your Mac.
2. Immediately press and hold the “D” key.
3. Release the “D” key when a progress bar appears.

For Macs with Apple silicon:

1. Shut down your Mac.
2. Press and hold the power button.
3. Keep holding until the Startup Options window appears. Then, press and hold “Command + D.”

Fix 8. Reinstall macOS

Reinstalling macOS will fix any deeper software issues that may be causing the Mac blue lines on screen. To do this:

1. Turn off your Mac. Then, turn it back on and immediately press and hold “Command + R”.
2. Enter your password and click “Next.”
3. Select “Reinstall macOS” and click “Continue.”

• Click “Continue” again. Then, follow the instructions to complete the installation.

Fix 9. Contact Support

If none of the above solutions work, the issue is likely hardware-related. At this stage, only Apple Support can help diagnose and fix the problem.

You can visit Apple's official support page to get in touch. Apple technicians will run in-depth diagnostics and offer repair options under warranty or AppleCare.

Part 4. Bonus Tip: The Best AI and PDF Editor Tool on Mac - UPDF for Mac

After fixing the blue lines, you’ll want your Mac ready for productive tasks. UPDF for Mac is the best tool that can help you work and study smarter. It is a powerful PDF editor with everything you need to view, edit, or organize your documents.

Plus, it has a built-in AI assistant powered by DeepSeek and ChatGPT 4.1. You can use it to summarize and translate documents, chat with PDFs and images, convert PDFs to mind maps, and more. Download UPDF via the button below to test it.

Key Features of UPDF

1. View PDFs in multiple layouts and eye-protection themes.
2. Edit PDF text, images, links, watermarks, backgrounds, and more.
3. Annotate with stickers, stamps, shapes, highlights, and more.
4. Collaborate with sticky notes, comments, and callouts
5. Create and fill out forms, whether interactive or non-interactive.
6. Batch process files to OCR, convert, compress, encrypt PDFs, and more.

UPDF has many other features that can help you study smarter and work more productively. If you want to learn more, read this review article or watch the video below.

Final Words

That wraps up our guide on how to fix blue lines on Mac screen. Whether the problem lies with the hardware or software, these fixes can help you get your Mac screen back in order. And if you want to handle your documents more productively, UPDF for Mac has you covered. With integrated AI and powerful PDF tools, you can work smarter and faster. Download and try it now!