いまvagrant1.9.0をダウンロード、インストールしてみたところ、ちょっとメッセージは違うものの、同じようにプラグインでエラーになりました。
E:\Vagrant\bento-CentOS6.8>vagrant -v
Vagrant 1.9.0
E:\Vagrant\bento-CentOS6.8>vagrant init bento/centos6.8
Vagrant failed to initialize at a very early stage:
The plugins failed to initialize correctly. This may be due to manual
modifications made within the Vagrant home directory. Vagrant can
attempt to automatically correct this issue by running:
vagrant plugin repair
If Vagrant was recently updated, this error may be due to incompatible
versions of dependencies. To fix this problem please remove and re-install
all plugins. Vagrant can attempt to do this automatically by running:
vagrant plugin expunge --reinstall
Error message given during initialization: Unable to resolve dependency: user requested 'vagrant-vbguest (> 0)'
E:\Vagrant\bento-CentOS6.8>
で、私の環境では、vagrant plugin expunge --reinstall
を試したところ、
E:\Vagrant\bento-CentOS6.8>vagrant plugin expunge --reinstall
This command permanently deletes all currently installed user plugins. It
should only be used when a repair command is unable to properly fix the
system.
Continue? [Y/N]:y
All user installed plugins have been removed from this Vagrant environment!
Vagrant will now attempt to reinstall user plugins that were removed.
Installing the 'vagrant-proxyconf' plugin. This can take a few minutes...
Fetching: micromachine-2.0.0.gem (100%)
Fetching: vagrant-proxyconf-1.5.2.gem (100%)
Fetching: vagrant-vbguest-0.13.0.gem (100%)
Installed the plugin 'vagrant-proxyconf (1.5.2)'!
Installing the 'vagrant-vbguest' plugin. This can take a few minutes...
Installed the plugin 'vagrant-vbguest (0.13.0)'!
E:\Vagrant\bento-CentOS6.8>vagrant plugin list
vagrant-proxyconf (1.5.2)
vagrant-share (1.1.6, system)
vagrant-vbguest (0.13.0)
E:\Vagrant\bento-CentOS6.8>
となり、プラグインを無事にアップデートでき、vagrant init bento/centos-6.8
も成功しました。