iMac speakers work (on boot), but not afterward?

[jman995x]

So, my iMac just started not playing sound. I woke it up and started to watch something I’d been watching the night before, but there was no sound. So, I rebooted the computer and there was no sound on restart, however when I did a hard reset (ie: held the power down for 4-5 seconds, let it sit for about 3 minutes, then restarted it), I got the apple start up “bong” and everything booted correctly, but still no audio for any Netflix, Amazon Prime, YouTube videos or iTunes. I looked at the “Sound” category in my “System Preferences” and there doesn’t appear to be “Internal Speakers” listed any longer in the “Output” category (but there was a program I used awhile ago called “Sound Siphon”, which has, in the past commandeered my sound system, so I not only put it in App Zapper, but then downloaded the official Sound Siphon Uninstaller as well). Rebooted once again and got the Apple startup “bong”, but still no sound afterwards, and it still says “Sound Siphon” in the “Sound”/“Output” category on my System Preferences).

So, having said all of that, we know that the logic board is still working or I wouldn’t get the startup “bong”.
Any suggestions on how to troubleshoot what has taken my sound system hostage?

Thanks in advance for any/all suggestions.

 

[jerwin]

is something plugged into the headphone jack?

check out Audio Midi Setup. It's in /Applications/Utilities

 

[chscag]

The iMac speakers are okay if you hear the POST chime on boot up. If Sound Siphon is showing up in your System Preferences Sound, that means it's still installed and has taken over the audio. You may have to download Sound Siphon again, install it, and this time instead of using App Zapper and then running the uninstaller, just run their uninstaller and then reboot.

 

[jman995x]

is something plugged into the headphone jack?

check out Audio Midi Setup. It's in /Applications/Utilities

Nope. Nothing has changed from last night (when everything was normal), and tonight (where the internal speakers only work for the boot up sound, then won’t produce sound at all).