Everything seems fine after installing Yosemite public beta, besides the audio part. I still can get the audio with headphone plugged in, but without headphone, the system keeps switching the output device to the AirPort Express Airplay instead of internal speaker. (I use the original AirPort Express as router but no audio device are connected to it) I try to click the internal speaker in System Preferences, or do it by option-click the audio icon on menu bar. But both doesn't work, I can click the "Internal Speaker" option but still no audio from speaker, when I checked the setting the AirPly option is checked again. The only time I can make the internal speaker works is when I disconnected from the AirPort Express. Without AirPlay detected, the internal speaker works again. Anyone has the issue too after Yosemite? I hope it isn't because of me using an older generation AirPort Express, it works fine I don't wanna get a new one yet.