MacBook Screen Lines, Flickering or Black Screen: Causes and Fixes

Seeing MacBook screen lines, a flickering image or a display that suddenly goes black is stressful, especially when you rely on your laptop every day. The good news is that a few simple tests can tell you whether you're dealing with a software glitch, a graphics problem or a hardware fault in the display itself. Here's how to narrow it down before booking a repair.

Common causes of lines and flickering

• Software or driver glitches after an update, which can cause flicker or odd artifacts.
• Display cable wear. The flexible cables that run through the hinge can wear out after years of opening and closing the lid.
• "Flexgate" on some 2016–2018 13-inch MacBook Pro models. Short display cables can wear, causing a "stage light" effect along the bottom of the screen, and eventually a backlight that cuts out when the lid is opened past a certain angle.
• Backlight failure. If the image is very faint and only visible with a flashlight, the backlight circuit or cable is a likely suspect.
• Physical or liquid damage. A drop, pressure on the lid or a spill can crack the panel or damage its connections, leaving lines, colour bands or black areas.
• Graphics or logic board faults, which can show lines on both the built-in and an external display.

Quick tests to narrow it down

1. Restart the Mac. If the lines vanish after a restart, a software glitch is more likely.
2. Take a screenshot (Shift-Command-3) and open it on another device. If the lines appear in the screenshot, the problem is in the graphics or software. If the screenshot looks clean, the display hardware or its cable is the likely cause.
3. Connect an external monitor. A clean image on the external display points toward the built-in screen or its cable. Lines on both point toward the logic board.
4. Move the lid slowly. If flicker, lines or blackouts change with the lid angle, a worn display cable is very likely.
5. Shine a flashlight on a black screen. If you can faintly see the desktop, the backlight has failed but the Mac itself is running.

Software fixes to try

1. Update macOS in System Settings > General > Software Update (or System Preferences > Software Update on older versions).
2. Start in Safe Mode. If flickering stops in Safe Mode, a login item, app or cache may be involved. See our guide on starting a MacBook in Safe Mode.
3. Check display settings. Turn off automatic brightness and True Tone temporarily in the Displays settings to rule them out.
4. Reset NVRAM on Intel Macs. NVRAM stores some display settings. Apple silicon Macs don't need a manual reset. Our guide on resetting SMC and NVRAM explains both.

When it's a hardware problem

If the screenshot is clean, the issue changes with lid angle, or an external display works perfectly, the fault is almost always in the display assembly or its cable. Software won't fix that. Lines that appear after a drop or a spill also point to hardware damage. Avoid pressing on the screen or repeatedly flexing the lid to "find the spot", as that can make cable damage worse.

Depending on the cause, the fix may be a display replacement, a cable or backlight repair, or board-level work when the graphics circuitry is at fault. A proper diagnosis tells you which one before you spend money.

Need MacBook screen repair in Ottawa?

Fix Revolution has more than 10 years of experience repairing Macs, including display and board-level repairs done in-house. We pick up your MacBook at home or at the office anywhere in Ottawa and Gatineau and bring it back once it's fixed, and most repairs take 1–2 business days depending on parts availability. Back up your data first if the Mac still works. For MacBook screen replacement in Ottawa, get a free quote or call 613-265-4349.

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