verr

C:\Program Files\Boot2Docker\Boot2Docker for Windows>boot2docker start -v
Boot2Docker-cli version: v1.7.0
Git commit: 7d89508
2015/07/30 11:39:07 executing: C:\Program Files\Oracle\VirtualBox\VBoxManage.exe
 showvminfo boot2docker-vm --machinereadable
2015/07/30 11:39:08 executing: C:\Program Files\Oracle\VirtualBox\VBoxManage.exe
 guestproperty set boot2docker-vm /VirtualBox/GuestAdd/SharedFolders/MountPrefix
 /
2015/07/30 11:39:08 executing: C:\Program Files\Oracle\VirtualBox\VBoxManage.exe
 guestproperty set boot2docker-vm /VirtualBox/GuestAdd/SharedFolders/MountDir /
2015/07/30 11:39:08 executing: C:\Program Files\Oracle\VirtualBox\VBoxManage.exe
 sharedfolder add boot2docker-vm --name c/Users --hostpath C:\Users --automount
VBoxManage.exe: error: Shared folder named 'c/Users' already exists
VBoxManage.exe: error: Details: code VBOX_E_OBJECT_IN_USE (0x80bb000c), componen
t SessionMachine, interface IMachine, callee IUnknown
VBoxManage.exe: error: Context: "CreateSharedFolder(Bstr(name).raw(), Bstr(hostp
ath).raw(), fWritable, fAutoMount)" at line 1015 of file VBoxManageMisc.cpp
2015/07/30 11:39:08 executing: C:\Program Files\Oracle\VirtualBox\VBoxManage.exe
 setextradata boot2docker-vm VBoxInternal2/SharedFoldersEnableSymlinksCreate/c/U
sers 1
2015/07/30 11:39:08 executing: C:\Program Files\Oracle\VirtualBox\VBoxManage.exe
 startvm boot2docker-vm --type headless
Waiting for VM "boot2docker-vm" to power on...
VM "boot2docker-vm" has been successfully started.
error in run: Failed to start machine "boot2docker-vm": exit status 1

C:\Program Files\Boot2Docker\Boot2Docker for Windows>