I had trouble to install freeBSD 10 in VirtualBox ( a virtualisation software ). It took me some time to find out a workaround to the blocking step : just after the password set up, installation abort by itself and said "An installation step has been aborted.. blabla"
To succeed install the OS, the tip was to escape to bootloader ( choice 3 ) and type :
set vfs.unmapped_buf_allowed=0 (enter)
Then proceed to FreeBSD installation as usual !