vmnetd

docker启动失败，诊断信息如下：
Information
Diagnostic ID D466944B-790A-45B7-A2D8-3CF4FEDFBAC6

Full output of the diagnostics from “Diagnose & Feedback” in the menu
Docker for Mac: version: 1.12.1 (2d5b4d9)
OS X: version 10.11.6 (build: 15G1004)
logs: /tmp/D466944B-790A-45B7-A2D8-3CF4FEDFBAC6/20161020-112100.tar.gz
failure: Docker.qcow2 missing: the VM has never been started
[ERROR] docker-cli
cannot find docker
docker-cli check failed with: Failure(“docker -v: timeout after 10.00s”)
[OK] virtualization kern.hv_support
[OK] menubar
[OK] moby-syslog
[OK] dns
[ERROR] disk
Docker.qcow2 missing: the VM has never been started
[OK] system
[OK] app
[ERROR] osxfs
com.docker.osxfs is not running
[OK] virtualization VT-X
[ERROR] db
/Users/davies/Library/Containers/com.docker.docker/Data/s40 does not exist
Unexpected error (No such file or directory) connecting to /Users/davies/Library/Containers/com.docker.docker/Data/s40
com.docker.db is not running
[ERROR] slirp
/Users/davies/Library/Containers/com.docker.docker/Data/s51 does not exist
Unexpected error (No such file or directory) connecting to /Users/davies/Library/Containers/com.docker.docker/Data/s51
com.docker.slirp is not running
[OK] logs
[OK] env
[ERROR] vmnetd
Connection refused (ECONNREFUSED) connecting to /var/tmp/com.docker.vmnetd.socket: check if service is running
/private/tmp/vmnetd/com.docker.vmnetd is not running
[OK] moby-console
[ERROR] moby
/Users/davies/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/console-ring does not exist
[ERROR] driver.amd64-linux
com.docker.driver.amd64-linux -db is not running
Failure: Could not upload diagnostic data to remote server (docker-diagnose exit code is 1)

解决办法：
$sudo mv /Library/PrivilegedHelperTools/com.docker.vmnetd /Library/PrivilegedHelperTools/com.docker.vmnetd.bak