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Toolbox migration assistant: invalid VMDK image descriptor


(Marzolfb) #1

Expected behavior

As a user, when pressing the “Copy” button on the initial “Toolbox migration assistant” window when launching Docker for Mac for the first time, I should not see an error.

Actual behavior

After pressing the “Copy” button, I see the error: “Failed to migrate images and containers: Error converting default volume: qemu-img: Could not open ‘/…/.docker/Machine/Machines/default/disk.vmdk’: invalid VMDK image descriptor”.

My only option from here is to press the Quit button. When I do this, Docker for Mac never “launches”. If I try to restart it again, I’m faced with the same prompt to Copy images from the existing VM. I can’t do anything at all with Docker for Mac unless I press the “No” button instead of the “Copy” button which will launch Docker for Mac without copying existing images (not what I wanted but I can live with it).


  • Docker for Mac Version 1.11.2-beta15 (build: 9168) (only found this version info after not electing to copy existing docker images and having Docker for Mac launch successfully)
  • Can’t launch "Diagnose & Feedback " from Moby Menu because Docker for Mac never launches (see above details)
  • On El Capitan - 10.11.5
  • Virtualbox version - 5.0.22
  • I was an original user of boot2docker and I went through a manual process to resize (increase) the disk space of that original VM (I followed the “Solution 2” instructions here )
    • Once Docker Toolbox became available it prompted to convert the VM to a new VM for me and it was successful doing that without issue
  • I’m going to continue running without copying existing images, so that I continue trying to use Docker for Mac

Steps to reproduce the behavior

Launch Docker for Mac for the first time and see the initial screen asking whether to migrate images from existing docker-machine VM and press the “Copy” button.