Issue Link : docker-archive/toolbox#673 (comment)
I use the workaround described by dsebastien in the issue linked in my previous reply with a small modification to avoid changing the calling shell environment. This is what I use as workaround now, in my ~/.bash_profile on Windows 10, Git Bash:
# Workaround for Docker for Windows in Git Bash.
docker()
{
(export MSYS_NO_PATHCONV=1; "docker.exe" "$@")
}