Macbook Pro 2017 - Can't ASR from internal drive to external drive

[Bernard_Huang]

Hi all,

I have a Macbook Pro 2017 model. The setup is:
- I have booted off an external disk that I created
- There is an internal disk image in the Macbook (obviously)
- I have a blank external disk connected as well.

So, I am now running the asr command to clone the image from internal drive to external blank drive
> sudo asr -source <internal drive volume> -target <external drive volume>

When I do this, I get the following error message
"
Couldn't get target recovery partition information
Someone has the disk open; see <rdar://problem/170858433>
"

I googled this error message, but couldn't find any useful information or workaround.
Can anyone help?

[Bernard_Huang]

O, btw, there is a work around for this.
Boot off the external macOS drive's recovery partition (hold down option to select it)
Then in the recovery partition, is it ok to run

> asr -source <internal drive volume> -target <external drive volume>

But I don't prefer to do it via the real OS. And I really want to understand that error message.