MacBook Charger Keeps Connecting and Disconnecting (MagSafe 3)

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MacBook Charger Keeps Connecting and Disconnecting (MagSafe 3)

I’ve been using the original Apple 140W power adapter and MagSafe 3 cable that came with my MacBook Pro 16-inch (M1, 2021) for about two years without any issues. However, starting a couple of days ago (after updating to macOS Sequoia 15.6), I noticed a problem:

When I use the MagSafe 3 cable with the original 140W power adapter, the charger keeps connecting and disconnecting repeatedly.

I hear the charging notification sound every few seconds.

The MagSafe indicator light keeps blinking instead of staying solid.

Here’s what I’ve tried and observed:

If I use an Apple-issued USB-C to USB-C cable (came with an iPhone) with the 140W adapter and connect it to a Thunderbolt 4 port, the MacBook charges without issues.

If I use the original MagSafe 3 cable with a third-party adapter, the laptop also charges fine.

The issue only happens when I use the Apple 140W adapter and the original MagSafe 3 cable together (the exact combination that worked perfectly for 2 years).

This started happening just a couple of days ago, around the time of a recent macOS update (Sequoia 15.6). Could this be related to the update, or is it likely a hardware issue with either the adapter or the cable?

Has anyone else experienced this? Any advice would be greatly appreciated.

MacBook Pro 16″, macOS 15.6

Posted on Aug 20, 2025 6:30 AM

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Answer 1

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Kudlayra

Level 1

8 points

Aug 26, 2025 9:09 AM in response to meow-rick

I’m experiencing the exact same issue.

I’ve been using the original Apple 140W power adapter and MagSafe 3 cable with my MacBook Pro 16-inch (M1, 2021) for nearly 3 mounths without any problems(I bought it brand new three months ago). But just recently—right after updating to macOS Sequoia 15.6—I started noticing the same symptoms:

-The MagSafe charger keeps connecting and disconnecting every few seconds

-I hear the charging chime repeatedly

-The MagSafe LED blinks instead of staying solid

I ran similar tests:

-USB-C to USB-C cable with the 140W adapter works fine

-MagSafe 3 cable with a third-party adapter also works

The issue only occurs when using the original MagSafe 3 cable with the original 140W adapter

It feels like something changed with the update. I’m also wondering whether it’s a firmware or software-related issue rather than hardware failure. Would be great to hear if others are seeing this too.

At the service center, they tested the MacBook with a different Apple power adapter and MagSafe 3 cable, but the issue persisted. They offered to take the device in for full diagnostics and potential repair, which could take up to a month. I declined, since I rely on this MacBook for daily work and can’t afford that kind of downtime.

For now, I’ve switched to charging my MacBook using a 100W USB-C to USB-C cable. It works reliably without any issues.

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MacBook Charger Keeps Connecting and Disconnecting (MagSafe 3)

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