一連のインストールの中で、yum update (all)したせいで、vagrant upした際に、こんなエラーが出るようになりました。 (実は、最初から出ていたのですが、読んでいませんでしたw) centos72: The guest additions on this VM do not match the installed version of centos72: VirtualBox! In most cases this is fine, but in rare cases it can centos72: prevent things such as shared folders from working properly. If yo u see centos72: shared folder errors, please make sure the guest additions within the centos72: virtual machine match the version of VirtualBox you have installed on centos72: your host and reload your VM. centos72: centos72: Guest Additions Version: 4.3.30 centos72: VirtualBox Version: 5.1 ==> centos72: Configuring and enabling network interfaces... ==> centos72: Mounting shared folders... centos72: /vagrant => D:/VM Vagrant was unable to mount VirtualBox shared folders. This is usually because the filesystem "vboxsf" is not available. This filesystem is made available via the VirtualBox Guest Add