Here are some tips for you, if you decide to do a live upgrade from PC-BSD 9.2 to PC-BSD 10:
- After your machine reboots for the first time, run pkg install -f to update all packages in order to match packages to the base system libraries.
- Make sure that /etc/loader.conf contains the entries that you need for your hardware. In my case, nvidia_load="YES" is important.
- After the aforementioned modifications, run grub-mkconfig -o /boot/grub/grub.cfg due to a known bug when upgrading grub.
- In my case, pc-updatemanager didn't install the base overlay correctly. I was missing several important libraries; these omissions prevented both ssh and sshd from running. To fix:
- Back up your /etc/ directory (and everything else -- I used a zfs snapshot -r tank)
- Download the base system overlay from your favorite mirror into a nice place like /var/tmp/
- cd /; tar xfym /var/tmp/base.txz
- Check for missing / broken libraries by using libchk (I uninstalled many packages that were discontinued / no longer applicable)