Unable to Eject Disk in Terminal

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2020macuser Author

Level 1

8 points

Unable to Eject Disk in Terminal

I have been having problems with my external hardrive. It has not been showing up under my “devices” in finder, my desktop nor any other computers. It does indicate that it’s on and I think working because my hardrive blinks a little white light. I have been able to see it in “System Information > USB” with all of it’s information which I believe is a good sign. And when I go to terminal it shows ups as well and I’m able to do the commands to get its info.

But when I go to use a command like [diskutil eject disk_ (disk number it’s labeled under) Terminal says “unable to find disk_” yet I know it exists as it’s literally displayed right above it. Anyone know what the issue could be? It happens with other commands too like mount.

MacBook Pro 13", macOS 10.13

Posted on Apr 18, 2020 12:07 PM

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Answer 1

Kappy

Level 10

362,007 points

Apr 18, 2020 2:00 PM in response to 2020macuser

That is listed as /dev/disk2s1 and shows that it is a Microsoft Basic Data disk. Is it possible that you have the MS program(s) open that use the disk? If so, then that is why you cannot eject it - it's in use. You could try preceding the command line with "sudo " in case it's required: sudo diskutil umount force /dev/disk2s1.

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Answer 2

Kappy

Level 10

362,007 points

Apr 18, 2020 1:35 PM in response to 2020macuser

Well, my first query is to ask if you used the proper disk no. and slice no. for your system. I just provided an example. It may be wrong for your computer.

If you had the correct device id, then I'm guessing there is a problem with the disk such that you cannot unmount that particular volume.

Can you try entering "diskutil list", then copy the resulting output and post it here?

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Answer 3

leroydouglas

Level 10

199,458 points

Apr 18, 2020 12:24 PM in response to 2020macuser

2020macuser wrote:

[diskutil eject disk_ (disk number it’s labeled under) Terminal says “unable to find disk_”

You can see more from the terminal, copy and paste:

man umount | more

or

man diskutil umount  | more

unmount | umount [force] device

Unmount a single volume. Force will force-unmount the volume

(less kind to any open files; see also umount (8)).

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Answer 4

2020macuser Author

Level 1

8 points

Apr 18, 2020 1:53 PM in response to Kappy

Heres the output. The external is the one I'm having trouble with.

/dev/disk0 (internal):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme 500.3 GB disk0

1: EFI EFI 314.6 MB disk0s1

2: Apple_APFS Container disk1 500.0 GB disk0s2

/dev/disk1 (synthesized):

#: TYPE NAME SIZE IDENTIFIER

0: APFS Container Scheme - +500.0 GB disk1

Physical Store disk0s2

1: APFS Volume Macintosh HD 455.8 GB disk1s1

2: APFS Volume Preboot 23.4 MB disk1s2

3: APFS Volume Recovery 519.0 MB disk1s3

4: APFS Volume VM 1.1 GB disk1s4

/dev/disk2 (external, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *4.0 TB disk2

1: Microsoft Basic Data 4.0 TB disk2s1

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Answer 5

2020macuser Author

Level 1

8 points

Apr 18, 2020 12:56 PM in response to leroydouglas

Thank you, this helps!

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Answer 6

2020macuser Author

Level 1

8 points

Apr 18, 2020 1:13 PM in response to Kappy

Hey, thank you. I’m new to all of this. Now with the proper command format I’m still getting “timed out” is there anything I’m doing wrong still or a way to fix that?

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Answer 7

Kappy

Level 10

362,007 points

Apr 18, 2020 12:25 PM in response to 2020macuser

You need to use a device ID in this form: /dev/disk_s_, where you replace the underscores with the appropriate id numbers such as /dev/disk0s2. You cannot eject a whole drive. An example:

    diskutil umount force /dev/disk0s2

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Unable to Eject Disk in Terminal

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