External drives self-eject on Mac mini M4

Question

commddot Author

Level 1

12 points

External drives self-eject on Mac mini M4

External drives self eject

2024 Mac mini M4 latest software

Restart Mac mini

Plug in one external drive

Wait 60 seconds

Run the command: log show --last 1m | grep -Ei "ejected|disconnect|overcurrent|port reset|IOUSB" | wc -l

Results in 44 disconnections, some of which fully eject the drive which occasionally self remounts

0–1Excellent — USB subsystem is healthy

2–5Normal background noise

5–15Mild instability, but acceptable

15–30Borderline — keep an eye on it

30–60Significant instability

60+Severe instability

Indicating Severe Instability

The computer was recently reset at an Apple Authorized Dealer

Posted on Apr 8, 2026 8:48 PM

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Answer 1

MartinR

Level 7

26,894 points

Apr 9, 2026 5:24 PM in response to commddot

You need to disclose the make(s) and model(s) of the external drive(s) you are using, exactly which port(s) on the Mac Mini you are connecting them to, what make/model cable(s) you are using and any/all other external USB devices also connected.

Please also clarify the exact test procedure(s) you are doing. The description you provided appears to involve 1 unidentified drive, a log extract for 1 minute showing no detailed results other than your claim to "44 disconnections". Without seeing the details there is nothing here to work with.

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Answer 2

Apr 9, 2026 1:35 AM in response to commddot

Were the drives connected via a hub and if so was it powered or unpowered?

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Answer 3

commddot Author

Level 1

12 points

Apr 9, 2026 7:04 PM in response to MartinR

Neither drive was on a hub.

One was powered one was not.

Each were tested with a variety of ports and cables. One was a brand new SSD and the other was an older powered Time Machine backup.

All were tested via First Aid in Recovery Mode.

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Answer 4

Allan Jones

Level 10

84,790 points

Apr 10, 2026 11:50 AM in response to commddot

Are you using macOS 26 Tahoe? I sensed an uptick in these reports when Tahoe was released and I have occasionally experienced them, but limited to one Mac and one bus-powered external drive.

Bug report are lost here as Apple does not participate. This will make sure an Apple employee sees your rtest results:

Feedback - macOS - Apple

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Answer 5

commddot Author

Level 1

12 points

Apr 9, 2026 7:03 PM in response to Ian R. Brown

Neither drive was on a hub.

One was powered one was not.

Each were tested with a variety of ports and cables. One was a brand new SSD and the other was an older powered Time Machine backup.

All were tested via First Aid in Recovery Mode.

Reply