MacBook external display disconnects when charging via USB-C

Question

Level 1

10 points

MacBook external display disconnects when charging via USB-C

USB-C External display keeps disconnecting and reconnecting while charging MacBook over the USB-C cable.

This has been as issue for years. I have the problem on different MacBooks (work, home) and different displays (Dell, LG). Step to reproduce :

When the MacBook battery is not full (let's say 50%).
Plug in a USB-C display that can charge the Mac.
Every minute the display disconnects (turns black, then the MacBook screen regains the main display. After 3s the MacBook reconnects to the display and again all windows move from one screen to another).
This keep happening until the MacBook reaches about 80%.

To solve that problem I need to charge the MacBook through another cable so that the USB-C cable connected to the display does not charge the MacBook.

MacBook Pro 16″, macOS 15.6

Posted on Nov 28, 2025 12:54 AM

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Answer 1

Top-ranking reply

azaksalmarzur28

Level 2

432 points

Nov 28, 2025 7:57 AM in response to irolley

Your issue happens because your 16-inch MacBook Pro needs 96–140W, but most monitors give only 60–65W, causing USB-C power renegotiation and display resets.

To fix it, you should:

✔ Charge MBP using original charger (best fix)

✔ Turn off optimized charging

✔ Use high-quality E-Marked 100W cable or Thunderbolt 4 cable

✔ Lower refresh rate or resolution

✔ Try other ports

✔ Update monitor firmware

✔ Disable monitor USB-C PD if possible

✔ Restart USB-C controller logic (full shutdown)

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Answer 2

Nov 28, 2025 6:31 AM in response to irolley

if your display does not stay connected, that suggests your cable is not up to spec or is longer than the maximum ONE meter length.

what Make&model display?

any other items in the display cable? dock, adapter?

what model-year MacBook Pro?

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