I've just made quite a big upgrade jump (v7 always worked well for me so didn't need to upgrade). Everything seemed to be OK but I've just noticed that some emails don't have any information in them and when I try to open them I get an access violation.
I know the email was correct before I upgraded as I still have the original on a different laptop. I made a backup before upgrading but don't really want to go back to it as I've pruned several hundred old emails since (and ran maintenance centre after I'd done it) and sent and received quite a few emails today.
It turns out it was an option in the plain text viewer. In case anyone else ever finds this message looking for an answer to the same problem... Go into Preferences. In the Viewer/Editor menu, in the "View plain text mesages" section, select the "plain text viewer no graphical smileys" option.