I was unable to get any sms readings after the 10.4.6 upgrade. Then I read somewhere that if you do a restart, not a power down, but a restart, it would work. So that's what I did (15" G4) and smackbook, amstracker and levelwidget all work now. If my battery runs down, they stop working again and I have to do a restart to get them going. I just hope that the disk protection feature still works when I'm not getting any sensor output.