VM in virtualbox is already locked for a session (or being unlocked)
<p>My VM in virtualbox can not start due to this error, I don't want to destroy it and reinstall it again, anyway to recover it ?</p>

<p>There was an error while executing <code>VBoxManage</code>, a CLI used by Vagrant
for controlling VirtualBox. The command and stderr is shown below.</p>

<pre><code>Command: ["modifyvm", "319fcce3-e8ff-4b6f-a641-3aee1df6543f", "--natpf1", "delete", "ssh"]

Stderr: VBoxManage: error: The machine 'centos64_c6402_1454036461345_59755' is already locked for a session (or being unlocked)
VBoxManage: error: Details: code VBOX_E_INVALID_OBJECT_STATE (0x80bb0007), component MachineWrap, interface IMachine, callee nsISupports
VBoxManage: error: Context: "LockMachine(a-&gt;session, LockType_Write)" at line 493 of file VBoxManageModifyVM.cpp
</code></pre>