The following error when docker-machine start.

Starting "default"...
(default) Check network to re-create if needed...
(default) Creating a new host-only adapter produced an error: /usr/local/bin/VBoxManage hostonlyif create failed:
(default) 0%...
(default) Progress state: NS_ERROR_FAILURE
(default) VBoxManage: error: Failed to create the host-only adapter
(default) VBoxManage: error: VBoxNetAdpCtl: Error while adding new interface: failed to open /dev/vboxnetctl: No such file or directory
(default) VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component HostNetworkInterfaceWrap, interface IHostNetworkInterface
(default) VBoxManage: error: Context: "RTEXITCODE handleCreate(HandlerArg *)" at line 94 of file VBoxManageHostonly.cpp
(default) 
(default) This is a known VirtualBox bug. Let's try to recover anyway...
Error setting up host only network on machine start: The host-only adapter we just created is not visible. This is a well known VirtualBox bug. You might want to uninstall it and reinstall at least version 5.0.12 that is is supposed to fix this issue

It says at least 5.0.12 and above, but it also happened in VirtualBox 5.2.44.

Solution

After all, I ran the script to reload the Kernel Extensions in the comments below and it was fixed.

https://github.com/Homebrew/homebrew-cask/issues/39369#issuecomment-339118861

I mean, I'm too familiar with this script, and the MacBook is too unstable, so I build the environment twice a year, but my GitHub Dockerfiles repository, which is a link to this comment, is the most useful. ..

that's all.

`Failed to create the host-only adapter` with docker-machine start`

Solution