Troubles with VirtualBox 4.3.26

[Warren Block]

Anyone else having trouble with 4.3.26?

Seems like I used VirtualBox very recently, but now it does not want to 
run at all.  The GUI sometimes does not start, and VBoxManage is 
similar.  'VBoxManage list vms' works maybe one in four times, otherwise 
just hanging:

   % VBoxManage list vms
   load: 0.04  cmd: VBoxManage 16522 [select] 7.77r 0.01u 0.00s 0% 15460k
   load: 0.21  cmd: VBoxManage 16522 [select] 66.05r 0.01u 0.00s 0% 15460k

Occasionally, it claims to have started a VM, but the VM does not 
actually start.  The GUI cannot start a VM:

   Failed to open a session for the virtual machine winxp.

   The virtual machine 'winxp' has terminated unexpectedly during startup with exit code 1 (0x1).

   Result Code: NS_ERROR_FAILURE (0x80004005)
   Component: Machine
   Interface: IMachine {480cf695-2d8d-4256-9c7c-cce4184fa048}

VirtualBox has been built without the VNC and WEBSERVICE options.  Both 
the main port and -kmod were rebuilt after updating to -STABLE 
today:

   FreeBSD lightning 10.1-STABLE FreeBSD 10.1-STABLE #0 r280696: Thu Mar 26 09:45:29 MDT 2015     root at lightning:/usr/obj/usr/src/sys/LIGHTNING  amd64

My hunch is this is something with the latest -STABLE, and the next 
tests will be to revert to a few days ago.