1. download https://www.virtualbox.org/attachment/ticket/14040/VBox-Win10-fix-14040.exe
2. run it as administrator
3. vagrant up using command line. it worked perfectly.

Or just get last virtualbox.

I had the same issue after upgrading to Windows 10. Installing the latest version of VirtualBox (5.0.14) and Vagrant (1.8.1) sorted this out for me.

However, I then had issues with the PhpStorm ssh-client as it kept giving me the following error message. SSH_MSG_DISCONNECT: 2 Too many authentication failures for vagrant.

This is the solution that worked for me. http://stackoverflow.com/a/35356427/2387780

On Windows if you have network issues (can't reach the guest) then just check that you don't have skype on before you run vagrant up.

Skype and perhaps other applications will make port 80 be unreachable for other apps like vagrant. So the first thing you do when you start your computer should be vagrant up. Also, if you have this issue it isn't enough (at least not for me) to quit skype. You need to restart the computer unfortunately.