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Apple MacBook Pro 16-inch (M4 family) troubleshooting

Apple MacBook Pro 16-inch (M4 family) (2024 M4 Pro/M4 Max 16-inch): the flicker reports; external monitors and MagSafe; charging and the 140W adapter; ports to test first; battery, and a fix for each symptom below.

The flicker reports
M4 MacBook Pro owners described an intermittent screen flicker after macOS 26.1 that a screenshot does not capture. The 16 inch shares the XDR panel with the 14 inch, so the same software first steps apply: update macOS, then test with an external display.

Won't startBattery drainNot chargingWi-FiBluetoothSlow

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Model numbers and patterns: 2024 M4 Pro/M4 Max 16-inch

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External monitors and MagSafe
Tom's Guide reported the 16 inch MacBook Pro line with MagSafe charging and external monitor problems at launch, so a monitor that goes blank is worth testing on another cable and port before service.
Charging and the 140W adapter
The 16-inch M4 Pro and M4 Max ship with a 140W USB-C power adapter and a USB-C to MagSafe 3 cable, and fast charging depends on that wattage. A lower-watt charger still charges, but a heavy job such as video export can drain the battery faster than a small charger refills it, so a laptop that loses charge while plugged in is often on the wrong charger.
Ports to test first
Besides MagSafe 3 the machine has three Thunderbolt 5 ports, an HDMI port and an SD card slot. When an external display or accessory misbehaves, move it to a different port and cable before suspecting the laptop, since a bad cable is far more common than a bad port.
Battery
Apple lists a 100-watt-hour battery for the 16-inch models. A battery that drains in a few hours under light use is a software or app problem to check in Activity Monitor and Battery settings before it is a battery replacement.

Manufacturer support for this product line. Apple Support — Apple product support. Official Apple model, operating-system, repair, connection and settings guidance.

Also read for this model. Apple Community — MacBook Pro (M4) display flickering after update; Tom's Guide — 16-inch MacBook Pro owners are reporting MagSafe charging and external monitor problems; Apple Support — MacBook Pro (16-inch, 2024) - Tech Specs.

Exact questions

Questions that only have an answer for the Apple MacBook Pro 16-inch (M4 family)

Is my MacBook Pro 16 flicker the display or the software?+

If it also shows on an external monitor, it is software or the GPU path; if only the built-in screen flickers, and more when the lid moves, it is the display hardware.

Why does my MacBook Pro 16 lose charge while plugged in?+

Usually a charger below 140W, a damaged cable or a very heavy workload. Try the original adapter and MagSafe cable and check Battery settings.

Which port should I use for an external monitor on a 16-inch M4 MacBook Pro?+

Any Thunderbolt 5 port or the HDMI port can drive a display; if one does not, try another port and a different cable before suspecting the Mac.