It looks like virtualbox-ext-pack was moved from multiverse to universe for Ubuntu 16.10, but virtualbox-ext-pack is now stuck in zesty-proposed since virtualbox is in multiverse.
> virtualbox-ext-pack/amd64 unsatisfiable Depends: virtualbox (>= 5.1) | virtualbox-5.1 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1624694 Title: please move virtualbox-ext-pack to universe To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/virtualbox-ext-pack/+bug/1624694/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
