突然之间，我无法再启动 Vagrant VM。错误如下：
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
default: Warning: Connection timeout. Retrying...
Timed out while waiting for the machine to boot. This means that
Vagrant was unable to communicate with the guest machine within
the configured ("config.vm.boot_timeout" value) time period.
If you look above, you should be able to see the error(s) that
Vagrant had when attempting to connect to the machine. These errors
are usually good hints as to what may be wrong.
If you're using a custom box, make sure that networking is properly
working and you're able to connect to the machine. It is a common
problem that networking isn't setup properly in these boxes.
Verify that authentication configurations are also setup properly,
as well.
我知道我在我的机器上做的唯一改变是升级到 Windows 10 秋季更新（又名 Threshold 2，又名更新 1511）。
什么原因导致虚拟机无法工作？
答案1
事实证明，Windows 10 更新在运行时会启用 Hyper-V（我曾看到过一个来源，但现在找不到了）。进入“程序和功能”，选择“打开或关闭 Windows 功能”，取消选中“Hyper-V”，然后重新启动即可解决问题。