When I updated from Avast 5.1.889 to 6.0.992 RC early yesterday the behavior shield was active. When I went from 6.0.992 to the final 6.0.1000 via the GUI the behavior shield stopped scanning. Anyway, I uninstalled Avast again today and did a clean install of 6.0.1000 and all is well, the behavior shield is active again. I knew something was up. This time I did a custom install and unchecked the gadget and the webrep plugin, not because they were causing issues, I just have no interest in them.