Machine: Problema al crear una máquina acoplable: "esta computadora no tiene VT-X / AMD-V embarcado, habilitarlo en el BIOS es obligatorio"

También viendo esto en Ubuntu 18.04.1:

$ docker-machine create default
Running pre-create checks...
Error with pre-create check: "This computer doesn't have VT-X/AMD-v enabled. Enabling it in the BIOS is mandatory"
$ lsb_release -d
Description:    Ubuntu 18.04.1 LTS
$ docker --version
Docker version 18.09.1, build 4c52b90
$ docker-machine --version
docker-machine version 0.16.1, build cce350d7
$ kvm-ok
INFO: /dev/kvm exists
KVM acceleration can be used

Saltarse el cheque funciona:

$ docker-machine create --virtualbox-no-vtx-check default
Running pre-create checks...
(default) Image cache directory does not exist, creating it at /home/nathan/.docker/machine/cache...
(default) No default Boot2Docker ISO found locally, downloading the latest release...
(default) Latest release for github.com/boot2docker/boot2docker is v18.09.1
(default) Downloading /home/nathan/.docker/machine/cache/boot2docker.iso from https://github.com/boot2docker/boot2docker/releases/download/v18.09.1/boot2docker.iso...
(default) 0%....10%....20%....30%....40%....50%....60%....70%....80%....90%....100%
Creating machine...
(default) Copying /home/nathan/.docker/machine/cache/boot2docker.iso to /home/nathan/.docker/machine/machines/default/boot2docker.iso...
(default) Creating VirtualBox VM...
(default) Creating SSH key...
(default) Starting the VM...
(default) Check network to re-create if needed...
(default) Found a new host-only adapter: "vboxnet0"
(default) Waiting for an IP...

Waiting for machine to be running, this may take a few minutes...
Detecting operating system of created instance...
Waiting for SSH to be available...
Detecting the provisioner...
Provisioning with boot2docker...
Copying certs to the local machine directory...
Copying certs to the remote machine...
Setting Docker configuration on the remote daemon...
Checking connection to Docker...
Docker is up and running!
To see how to connect your Docker Client to the Docker Engine running on this virtual machine, run: docker-machine env default

Creo que este error exclusivo de AMD se introdujo en 5a8ce1ae43de21b0b875189293267164f37acf5e

Hay una solución en https://github.com/docker/machine/issues/4669

@ Mayur-Sapre2: ¿ejecutas AMD? ¿Puedes probarlo?

Lo resolví así
docker-machine.exe -D create -d virtualbox --virtualbox-memory 2048 --virtualbox-no-vtx-check default

Finalmente arreglado en # 4679