Unable to exec any docker job locally from Windows 10 host (with Docker Toolbox)

Summary

Unable to execute whatsoever job locally from Windows 10 host when executor is docker (Docker Toolbox).

Steps to reproduce

.gitlab-ci.yml

image: alpine:3.10
test:
  script:
  - echo "Minimal failure"

Actual behavior

gitlab-runner exec docker test

Runtime platform                                    arch=amd64 os=windows pid=11500 revision=a987417a version=12.2.0
Running with gitlab-runner 12.2.0 (a987417a)
ERROR: Job failed: invalid volume specification: "C:\\Users\\XXX\\repo:C:\\Users\\XXX\\repo:ro"
FATAL: invalid volume specification: "C:\\Users\\XXX\\repo:C:\\Users\\XXX\\repo:ro"

gitlab-runner exec docker --docker-volumes "//home/XXX/repo:/home/XXX/repo" test

ERROR: Job failed: invalid volume specification: "//home/XXX/repo:/home/XXX/repo"
FATAL: invalid volume specification: "//home/XXX/repo:/home/XXX/repo"

docker run -it --rm -v "//home/XXX/repo:/home/XXX/repo" "alpine:3.10" sh -c "cd /home/XXX/repo && tail -1 .gitlab-ci.yml"

  - echo "Minimal failure"

Additionally:

• shell executor works fine
• docker executor works fine when job comes from Gitlab pipeline (gitlab-runner runs as a specific runner)

Expected behavior

Gitlab-runner job test succeed and output is Minimal failure.

Environment description

Machine setup:

• Windows 10 Home 1903 x64 (build 18 362)
• Docker Toolbox (19.03.1)
• VirtualBox 6.0.12
  • docker default machine is setup with a permanent auto-mounted shared folder : C:\Users\XXX → home/XXX

docker info

Client:
 Debug Mode: false

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 1
 Server Version: 18.09.9
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: true
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Plugins:
  Volume: local
  Network: bridge host macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 894b81a4b802e4eb2a91d1ce216b8817763c29fb
 runc version: 425e105d5a03fabd737a126ad93d62a9eeede87f
 init version: fec3683
 Security Options:
  seccomp
   Profile: default
 Kernel Version: 4.14.141-boot2docker
 Operating System: Boot2Docker 18.09.9 (TCL 8.2.1)
 OSType: linux
 Architecture: x86_64
 CPUs: 1
 Total Memory: 989.4MiB
 Name: default
 ID: …
 Docker Root Dir: /mnt/sda1/var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
  provider=virtualbox
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false
 Product License: Community Engine

config.toml (unlike local execution, my registered gitlab-runner service works well as a specific runner over the Gitlab pipeline)

concurrent = 1
check_interval = 0

[session_server]
  session_timeout = 1800

[[runners]]
  name = "W10-XXX-PC"
  url = "https://gitlab.com/"
  token = "$TOKEN"
  executor = "docker"
  [runners.docker]
    host = "tcp://...:2376"
    tls_cert_path = "C:\\Users\\XXX\\.docker\\machine\\machines\\default"
    tls_verify = true
    image = "alpine:3.10"
    privileged = false
    disable_entrypoint_overwrite = false
    oom_kill_disable = false
    disable_cache = false
    volumes = ["/cache"]
    shm_size = 0

Used GitLab Runner version

Version:      12.2.0
Git revision: a987417a
Git branch:   12-2-stable
GO version:   go1.8.7
Built:        2019-08-22T13:06:07+0000
OS/Arch:      windows/amd64