After upgrading to Mac OS X Big Sur I tried to spin up my Dinghy machine doing dinghy up and I got this error:

Starting the dinghy VM...
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
Traceback (most recent call last):
	9: from /usr/local/bin/_dinghy_command:12:in `<main>'
	8: from /usr/local/Cellar/dinghy/4.6.5/cli/thor/lib/thor/base.rb:440:in `start'
	7: from /usr/local/Cellar/dinghy/4.6.5/cli/thor/lib/thor.rb:359:in `dispatch'
	6: from /usr/local/Cellar/dinghy/4.6.5/cli/thor/lib/thor/invocation.rb:126:in `invoke_command'
	5: from /usr/local/Cellar/dinghy/4.6.5/cli/thor/lib/thor/command.rb:27:in `run'
	4: from /usr/local/Cellar/dinghy/4.6.5/cli/cli.rb:93:in `up'
	3: from /usr/local/Cellar/dinghy/4.6.5/cli/cli.rb:271:in `start_services'
	2: from /usr/local/Cellar/dinghy/4.6.5/cli/dinghy/machine.rb:25:in `up'
	1: from /usr/local/Cellar/dinghy/4.6.5/cli/dinghy/machine.rb:126:in `system'
/usr/local/Cellar/dinghy/4.6.5/cli/dinghy/system.rb:18:in `system': Failure calling `docker-machine start dinghy` (System::Failure)

Turns out that was complaining about version 5.0 but I was already on 6.1.

The Docker Machine was here: docker-machine ls:

NAME     ACTIVE   DRIVER       STATE     URL   SWARM   DOCKER    ERRORS
dinghy   -        virtualbox   Stopped                 Unknown

Trying to manually start the Dinghy machine was failing too: docker-machine start dinghy:

Starting "dinghy"...
(dinghy) Check network to re-create if needed...
(dinghy) Creating a new host-only adapter produced an error: /usr/local/bin/VBoxManage hostonlyif create failed:
(dinghy) 0%...
(dinghy) Progress state: NS_ERROR_FAILURE
(dinghy) VBoxManage: error: Failed to create the host-only adapter
(dinghy) VBoxManage: error: VBoxNetAdpCtl: Error while adding new interface: failed to open /dev/vboxnetctl: No such file or directory
(dinghy) VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component HostNetworkInterfaceWrap, interface IHostNetworkInterface
(dinghy) VBoxManage: error: Context: "RTEXITCODE handleCreate(HandlerArg *)" at line 95 of file VBoxManageHostonly.cpp
(dinghy)
(dinghy) 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

Also I tried regenerating the certificates: docker-machine regenerate-certs dinghy --client-certs:

Regenerate TLS machine certs?  Warning: this is irreversible. (y/n): y
Regenerating TLS certificates
Regenerating local certificates
Waiting for SSH to be available...
Too many retries waiting for SSH to be available.  Last error: Maximum number of retries (60) exceeded

Finally I decided to recreate the Dinghy machine, first I destroid the current machine: dinghy destroy:

Stopping the FsEvents daemon
Stopping the dinghy VM...
Stopping NFS daemon, this will require sudo
Password:
About to remove dinghy
WARNING: This action will delete both local reference and remote instance.
Are you sure? (y/n): y
Successfully removed dinghy

I created a new one: dinghy create --disk=100000 --provider=virtualbox:

Creating the dinghy VM...
Running pre-create checks...
Creating machine...
(dinghy) Copying /Users/albert/.docker/machine/cache/boot2docker.iso to /Users/albert/.docker/machine/machines/dinghy/boot2docker.iso...
(dinghy) Creating VirtualBox VM...
(dinghy) Creating SSH key...
(dinghy) Starting the VM...
(dinghy) Check network to re-create if needed...
(dinghy) Creating a new host-only adapter produced an error: /usr/local/bin/VBoxManage hostonlyif create failed:
(dinghy) 0%...
(dinghy) Progress state: NS_ERROR_FAILURE
(dinghy) VBoxManage: error: Failed to create the host-only adapter
(dinghy) VBoxManage: error: VBoxNetAdpCtl: Error while adding new interface: failed to open /dev/vboxnetctl: No such file or directory
(dinghy) VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component HostNetworkInterfaceWrap, interface IHostNetworkInterface
(dinghy) VBoxManage: error: Context: "RTEXITCODE handleCreate(HandlerArg *)" at line 95 of file VBoxManageHostonly.cpp
(dinghy)
(dinghy) This is a known VirtualBox bug. Let's try to recover anyway...
Error creating machine: Error in driver during machine creation: 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
Traceback (most recent call last):
	8: from /usr/local/bin/_dinghy_command:12:in `<main>'
	7: from /usr/local/Cellar/dinghy/4.6.5/cli/thor/lib/thor/base.rb:440:in `start'
	6: from /usr/local/Cellar/dinghy/4.6.5/cli/thor/lib/thor.rb:359:in `dispatch'
	5: from /usr/local/Cellar/dinghy/4.6.5/cli/thor/lib/thor/invocation.rb:126:in `invoke_command'
	4: from /usr/local/Cellar/dinghy/4.6.5/cli/thor/lib/thor/command.rb:27:in `run'
	3: from /usr/local/Cellar/dinghy/4.6.5/cli/cli.rb:65:in `create'
	2: from /usr/local/Cellar/dinghy/4.6.5/cli/dinghy/machine.rb:16:in `create'
	1: from /usr/local/Cellar/dinghy/4.6.5/cli/dinghy/machine.rb:130:in `system_print'
/usr/local/Cellar/dinghy/4.6.5/cli/dinghy/system.rb:8:in `system_print': Failure calling `docker-machine create -d virtualbox --virtualbox-memory 2048 --virtualbox-cpu-count 1 --virtualbox-disk-size 100000 --virtualbox-no-share dinghy` (System::Failure)

I got another error creating.

The Solution

Turns out that Mac OS X was blocking Virtualbox, to fix I did the following:

  1. Open Settings > Security&Privacy
  2. Check for the blocking message, should be something similar to System software from 'Oracle' developer was blocked from loading
  3. Click to Allow button
  4. Destroy the previous maching: dinghy destroy
  5. Create a new one dinghy create --disk=100000 --provider=virtualbox