External drives disconnect automatically, sometimes reconnect automatically to Macbook Pro

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Level 1

4 points

External drives disconnect automatically, sometimes reconnect automatically to Macbook Pro

While copying large amounts of data (e.g. 77 GB) between external drives (e.g. HD/SSD->HD/SSD, SD card->HD/SSD) attached via USB-C, or even while doing absolutely nothing, Macbook disconnects and sometimes re-connects the external units.

This causes/might cause data corruption and possibly harm the physical drives.

The/similar problem(s) seems to exist for other Mac models too, e.g. Mac Mini.

The problem seems to be an old, but *ongoing* problem, since I've found others having similar problems with much newer Macs than my MacBook Pro (15-inch, 2018).

Any ideas how to solve it once and for all?

MacBook Pro 15″, macOS 10.14

Posted on Aug 28, 2024 3:50 AM

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Answer 1

Aug 31, 2024 9:14 PM in response to GudmundAres

If you are connecting laptop-class drives (2.5", bus powered) directly to the Mac, try connecting them by means of a powered dock or hub – one that provides power from a wall adapter.

If these are 2.5" laptop drives in external cases, these cases may be less robust than others. You might try using different cases.

Another possible weak point may be a lower quality USB-C connecting cable. Try using a quality cable from a known manufacturer.

You can shop any number of hardware providers, but many folks here in the Communities swear by OWC/macsales for their Mac accessories. They know their Macs and are pretty good to work with if you call.

https://eshop.macsales.com/

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Answer 2

GudmundAres Author

Level 1

4 points

Sep 1, 2024 11:31 PM in response to D.I. Johnson

I get this with both with externally powered drives and with any kind of cables, expensive brand cables or noname cables. Ditto regarding cable length, which might otherwise be an issue.

What I've heard from people who normally know a very great deal about hardware matters is that Apple sticks on the low side regarding power output via USB C. Of course, I'd rather not have that to be true, so I'm hoping for a true solution. Unless that power output can be influenced by me as a user, of course.

FWIW, since even externally powered drives also get this error, the output problem should then be one of signal strength rather than power supply.

FWIW, it has also happened with SD cards in various external card readers, so... Either those adapters/readers are also a problem (which would be rather a big problem, since there aren't any built into modern macs!), or there's a general OS problem with external units.

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External drives disconnect automatically, sometimes reconnect automatically to Macbook Pro

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