A note is required in CDK Installation guide.
Users who wish to upgrade to newer version of Vagrant, Eg. 1.7.4 to 1.8.1 need to remove the .vagrant.d folder which contains metadata and plugins to prevent conflicts between different versions of Vagrant. Not doing so, throws up errors.
Ref.: https://github.com/projectatomic/adb-atomic-developer-bundle/issues/500