phantomjs: The guest additions on this VM do not match the installed version

==> phantomjs: Checking for guest additions in VM...
phantomjs: The guest additions on this VM do not match the installed version of
phantomjs: VirtualBox! In most cases this is fine, but in rare cases it can
phantomjs: prevent things such as shared folders from working properly. If you see
phantomjs: shared folder errors, please make sure the guest additions within the
phantomjs: virtual machine match the version of VirtualBox you have installed on
phantomjs: your host and reload your VM.
phantomjs:
phantomjs: Guest Additions Version: 5.0.10
phantomjs: VirtualBox Version: 4.3

Solution

C:\dev\>vagrant plugin install vagrant-vbguest
Installing the 'vagrant-vbguest' plugin. This can take a few minutes...
Installed the plugin 'vagrant-vbguest (0.11.0)'!

C:\dev\vagrant\supervm>vagrant reload