这里有很多很好的答案，我不能全部读完，但是，我只是来给我的一点贡献。我有两个不同的问题:

vagrant up wasn't able to find my ssh 'id_rsa' (because I didn't have it yet, at that time): I ran ssh-keygen -t rsa -b 4096 -C "myemailaddress@mydomain.com", based on this GitHub's article, and voilá, steped through that; Then, I got the same problem of this question "Warning: Connection timed out. Retrying...", eternally...: So, after reading a lot, I've restarted my system and looked at my BIOS (F2 to get there, on PC), and there were Virtualization disabled. I've enabled that, saved, and started the system once again, to check if it has changed anything.

从那以后，流浪起来就像有魔力一样!现在是凌晨4点，但它还在跑!多酷啊，hã?我知道很少有像我这样的受虐狂开发者会在Windows上尝试这个，特别是在Windows 10上，我只是无法不忘记来这里并留下我的话…另一个重要的信息，是，我试图设置Laravel 5，使用Homestead, VirtualBox，作曲家等。这是有效的。所以，希望这个答案能对你有所帮助，就像这个问题和答案对我有所帮助一样。祝福你。G-bye !

对我有帮助的是在BIOS中启用虚拟化，因为机器无法启动。

我解决的方法是，在Windows上键入两次“cmd”(或“ctrl+C”)，然后退出连接失败的屏幕。

然后，我可以通过SSH (vagrant SSH)连接，并自己查看错误。

在我的例子中，这是一个输入错误的路径。

如果您正在使用包装层(如Kitchen CI)，并且正在运行32b主机，则必须抢先安装Vagrant盒子。它们的默认提供程序是二进制文件的opscode“家族”。

所以在厨房创建default-ubuntu-1204之前，请确保您使用:

vagrant box add default-ubuntu-1204 http://opscode-vm-bento.s3.amazonaws.com/vagrant/virtualbox/opscode_ubuntu-12.04-i386_chef-provisionerless.box

如果您的主机不支持字大小虚拟化，则使用32b映像

我也有同样的问题。我认为问题可能是SSH密钥(错误的文件定位或其他东西，但我检查了很多次)，但你可能总是在配置部分添加用户名和密码(不使用SSH密钥)和运行gui，所以Vagrantfile中的代码应该看起来或多或少如下:

Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|

  config.ssh.username = "vagrant"
  config.ssh.password = "vagrant"

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

In my case even if GUI was displayed I got black screen (no errors or possibility to login or anything else) and in console I got the Error: Connection timeout. Retrying... many times. I made sure I had VT-x (virtualization) enabled in BIOS, I checked many combinations of versions of both Virtual Box and Vagrant together and many Vagrant boxes (for some of them I didn't have black screen in GUI but still have connection problems). Finally I've updated VirtualBox and Vagrant again to the last versions and the problem still occurred.

最关键的是在运行vagrantup(使用Vagrantfile中的GUI)后，在VirtualBox中查看图标，如下图所示

虽然我在VirtualPC中没有错误(没有VT-x未启用的警告)，但我的V图标是灰色的，所以这意味着VT-x被禁用。正如我说的，我一直在我的BIOS中启用它。

Finally I realized the problem might by HYPER-V which I also installed and enabled to test sites on older Internet Explorer. I went to Windows Control Panel -> Programs and functions / Software and choose from the menu on left Turn on or Turn off Windows functions (hope you will find those, I use Polish Windows so don't know exact English names). I turned off Hyper-V, restarted PC and after running Virtual Box and vagrant up I finally had no errors, in GUI I have login screen and my V icon stopped to be gray.

我浪费了很多时间来解决这个问题(和许多电脑重启)，所以我希望这可能对任何在Windows上有问题的人有帮助-确保你在控制面板中关闭了Hyper-V。

我通过在/etc/fstab中添加一个新条目来测试我的vagrant VM中挂载的文件夹。后来我注销了，跑了个流浪汉，但当我跑了个流浪汉，我得到:

SSH auth method: private key
Warning: Remote connection disconnect. Retrying...

I read all these posts and tried all the ones that seemed relevant for my case (except for vagrant destroy, which would have certainly fixed my problem, but was a last resort in my case). The post by @Kiee gave me the idea to try to boot my VM directly from the VirtualBox GUI. During the boot process the VM halted itself and was asking me if I wanted to skip mounting the test folder that I had added earlier to /etc/fstab. (That's why vagrant couldn't boot the VM.) After answering 'NO' the VM booted no problem. I logged in, removed the naughty line from my fstab, and shutdown the VM.

在那之后，流浪汉就能很好地踢足球了。

外卖吗?如果突然间vagrant无法引导回您的VM，请尝试直接从提供商引导(在我的情况下是VirtualBox)。您的引导可能挂起了与SSH完全无关的东西。