In the past with VMware and Virtualbox it was Recommended to setup your virtual environment as 64-bit FreeBSD. This no longer works. You must set it up as a 32-bit FreeBSD. I tried under VMWare Desktop and Fusion and also the latest Virtualbox builds and trying to install the i386 ISO setup as a 64-bit FreeBSD hangs every time under all products. Most of the times it would hang about 5% of the way into the install. On the rare occasion that it spit out an error it said to look at .tmp/.pcsyinstall/pc-sysinstall.log but that folder/file did not exist.

Once I setup the virtual environment as 32-bit FreeBSD installations work every time on all products.