Error while waiting for device: The emulator process for AVD Nexus_5X_API_23 was killed

If you see this error:

• Power off your VirtualBox Virtual Machines
• Shut down your Docker daemon

~/Library/Android/sdk/tools/emulator -netdelay none -netspeed full -avd Nexus_6_API_23
emulator: WARNING: VM heap size set below hardware specified minimum of 384MB
emulator: WARNING: Setting VM heap size to 384MB
Hax is enabled
Hax ram_size 0x60000000
HAX is working and emulator runs in fast virt mode.
console on port 5554, ADB on port 5555
Failed to sync vcpu reg
emulator: ERROR: Unfortunately, there's an incompatibility between HAXM hypervisor and VirtualBox 4.3.30+ which doesn't allow multiple hypervisors to co-exist.  It is being actively worked on; you can find out more about the issue at http://b.android.com/197915 (Android) and https://www.virtualbox.org/ticket/14294 (VirtualBox)
Failed to sync vcpu reg
Failed to sync vcpu reg
Internal error: initial hax sync failed