Are you trying to connect to a TLS-enabled daemon without TLS?

Docker Engine General
15

This issue also happened to my machine. Using Docker Toolbox 1.9.0 and Windows 8.1 Pro.
To fix the issue I did the following:

  1. Uninstall both Docker Toolbox and Virtual Box
  2. Remove folders .docker and .VirtualBox under folder c:\Users\{windows account username}\
  3. Remove all “VirtualBox Host-Only Ethernet Adapter” from Device Manager window
  4. Restart machine
  5. Re-install Docker Toolbox
  6. Click Docker Quick Start Terminal