我也遇到过同样的问题。我通过在BIOS设置中启用虚拟化来解决这个问题。

我解决了这个问题，如果其他人有类似的问题，我会回答。

我所做的是:我启用了虚拟框的GUI，让它在启动时等待输入，以选择我是想直接引导到ubuntu还是safemode等等。

要打开GUI，你必须把这个放在你的Vagrantfile配置中:

config.vm.provider :virtualbox do |vb|
  vb.gui = true
end

It used to help to switch to trusty32, but the situation now got worse again: I tried to use Homestead 2.0 and now I've got the Connection Timeout problem again, which would't usually be a problem, because switching to 32bit helped before. But now I can't just add a line like config.vm.box="ubuntu/trusty32" because we don't have a classic Homestead.yaml file anymore, the values in the new 2.0 Homestead.yaml file just seem to be inserted into the real one in the background and there ist no Vagrantfile available that I could manually edit ...

希望有人能帮忙……

我在《Vagrant 1.6.5》和《Virtual Box 4.3.16》中也遇到了同样的问题。 在https://github.com/mitchellh/vagrant/issues/4470上描述的解决方案对我来说很好，我只需要删除VirtualBox 4.3.16并安装旧版本4.3.12。

My solution turned out to be none of the above exactly. I'm running Ubuntu 14 as guest inside a Windows 7 host. I had been running this vagrant box fine, but I started it up again after not using it for a couple of months, and it kept coming up with the SSH connection timeout. It turned out that somehow the key pair didn't work - so I copied the Vagrant public key into Ubuntu according to the instructions on this page. But that wasn't all. I then discovered that the private key in my base box was different than the private key here. Putting this private key in as the vagrant_private_key file in C:\Users\your-user.vagrant.d\boxes\vagrant-box-name\nnnnnnnn\virtualbox after placing the public key into Ubuntu fixed the problem.

就我个人而言，Tunnelblick VPN软件阻断了连接。现在当我启动新的虚拟机时，我临时禁用Tunnelblick。