VirtualBox 5.1 and Vagrant 1.8.5 - please avoid these versions

[Tirloni, Giovanni]

Hi,

 Today I was testing the new releases of VirtualBox and Vagrant. They have many issues independently (previous non-Vagrant VMs fail to start, vagrant can't provision new boxes, etc).

 The last known versions to work properly seem to be VirtualBox 5.0.24 (or possibly .26) and Vagrant 1.8.4

 For anyone that installed the updates and wants to downgrade, you can grab the old installers/packages here:

https://releases.hashicorp.com/vagrant/1.8.4/
https://www.virtualbox.org/wiki/Download_Old_Builds_5_0

Regards,
Giovanni