I use a Moshi Mini DisplayPort to HDMI adapter (as recommended by Apple Care) to output 1080p with audio over hdmi via mini displayport on my 27" iMac (core2Duo model). Upgrading from 10.6.3 to 10.6.4 has caused me to lose the audio through the Mini DisplayPort. I had been getting both audio and video perfectly fine until this upgrade and now in system preferences, only the internal speakers are given as an option. In other words, 10.6.4 seems to have broken my audio out by removing the choice. No other system changes have been made that could account for this. I'm using the same cables and tv. I've reconnected everything, rebooted and also power cycled the tv, all to no effect. Has this happened to anyone else? Does anyone know a fix? Please help!