Virtualbox virtual disk hang

[Steven Wallace]

Ever since I have upgraded to FreeBSD 11.1 early this year, VirtualBox's 
virtual disks will hang randomly.   I have to SATA emulated devices which are
configured as FLAT devices to /dev/sd#x on two separate physical drives.

I have upgraded Virtualbox consistently, even recently compiling the new 5.2.0 
version.

The virtualbox's disk icon will stay constant green (or sometimes red).   I 
usually use Windows 7 guest.   Sometimes after 30 minutes Windows 7 will 
continue as if it could not read the drive.  Other times it will give a blue 
screen of death.

It may work fine for a month, then consistently hang within  a few minutes of 
use in Windows 7.

If anyone has a clue as to what may be the source of the problem please chime 
in.

Sincerely,

Steven Wallace