Docker issue in sharing folder on windows host through VBoxManage command
<p>Let me first tell that I am able to share a folder from windows host using VirtualBox UI. 
I am just trying to do the same through the command line so I do not have to open the UI every time. I am using the following command to create the shared folder:</p>

<pre>"C:/Program Files/Oracle/VirtualBox/VBoxManage" sharedfolder add default -name myNewDockerVolume -hostpath C:/Users/kishore/Documents/myNewDockerVolume
</pre>

<p>And I get the following error for this:</p>

<pre>$ "C:/Program Files/Oracle/VirtualBox/VBoxManage" sharedfolder add default -name myNewDockerVolume -hostpath C:/Users/kishore/Documents/myNewDockerVolume
VBoxManage.exe: error: The machine 'default' is already locked for a session (or being unlocked)
VBoxManage.exe: error: Details: code VBOX_E_INVALID_OBJECT_STATE (0x80bb0007), component MachineWrap, interface IMachine, callee IUnknown
VBoxManage.exe: error: Context: "LockMachine(a->session, LockType_Write)" at line 1012 of file VBoxManageMisc.cpp
</pre>

<p>I can see only one docker machine right now:</p>

<pre>$ docker-machine ls
NAME      ACTIVE   DRIVER       STATE     URL                         SWARM   DOCKER    ERRORS
default   *        virtualbox   Running   tcp://192.168.99.100:2376           v1.10.1</pre>

<p>Am I doing something wrong here ? </p>