I can confirm, this is broken in v20160822.0.0. I tried rolling back to v20160805.0.0, but that also seems to fail.
ubuntu@ubuntu-xenial:~$ modinfo vboxguest filename: /lib/modules/4.4.0-34-generic/kernel/ubuntu/vbox/vboxguest/vboxguest.ko version: 5.0.18_Ubuntu license: GPL description: Oracle VM VirtualBox Guest Additions for Linux Module author: Oracle Corporation srcversion: A2B0E3228AD033CF730FD74 alias: pci:v000080EEd0000CAFEsv00000000sd00000000bc*sc*i* depends: intree: Y vermagic: 4.4.0-34-generic SMP mod_unload modversions I'm currently on VirtualBox Version 5.1.4 r110228. I'm able to fix this by downloading v5.1.4 guest additions from here: http://download.virtualbox.org/virtualbox/5.1.4/ Note, you'll need to install the following packages in order to compile the guest additions: * gcc * build-essentials * linuz-headers-$(uname-a) // your architecture here -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1565985 Title: vagrant vb ubuntu/xenial64 cannot mount synced folders To manage notifications about this bug go to: https://bugs.launchpad.net/cloud-images/+bug/1565985/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
