Catalina does not play nice with USB drives. Won't unmount, erase, eject.

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Level 1

8 points

Catalina does not play nice with USB drives. Won't unmount, erase, eject.

2019 MBP with Catalina. I've tested multiple USB drives and multiple dongles, adapters, USB hubs.

The drive works at first but if you try to format it, partition it, erase it then it breaks and Catalina refuses to work with the drive.

Try to erase a drive:

Disk object invalid or unable to serialize. : (-69810)

Try to mount a partition on the drive:

Could not mount. (com.apple.DiskManagement.disenter error 0.)

Try to eject a drive:

Failed to eject “Kingston DataTraveler SE9 Media” because it is currently in use.

No.. it isn't... because the drive isn't even plugged in anymore.

If i restart my computer, then the drives work again. Appears to be a macOS software bug to me. Would love to know how to fix this without restarting my computer.

Posted on Feb 22, 2021 10:54 AM

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Answer 1

a brody

Level 10

85,412 points

Feb 22, 2021 5:30 PM in response to unformatt

Make sure the drive has its own power. Even if it means putting it on an AC powered USB hub. Apple's Energy Saver which is enabled when you close the lid can trigger problems with third party USB items not familiar with its low power mode.

Apple menu -> System Preferences -> Energy Saver

helps avoid most issues by allowing you to not put hard disks to sleep ever.

But some hard drives may still misbehave.

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