Stderr: VBoxManage.exe: error: Could not rename the directory

I am not a big fan of Vagrant, its behavior is way too erratic and opaque for me. When it works we are happy, when it fails - and it fails way too often - we are left googling sparse and stern documentation.

This new error "Stderr: VBoxManage.exe: error: Could not rename the directory" could be fixed only after LOTS of googling and trial and error:

Vagrant.configure("2") do |config2|
  # ... (other config)
  config2.vm.provider :virtualbox do |vb|
      vb.name = "jkstest"
  end
end

This should be added just after the config.vm.box_url clause, and BEFORE any customize.

How frustrating.

Despite this settings, my VB is created in C:\Users\myuser\VirtualBox VMs\workspaceJKS_1377339021, rather than in the jkstest folder.