Very Odd System Event Sound


Issue Description and Background
Lately an "unknown system event" triggers an audible sound on my iMac 27 inch, running High Sierra 10.13.6. This sound occurs very frequently and generates at the same volume as the system sound is set, making video watching or even general focusing-on-work on the iMac, essentially impossible.

This audible sound is generated even though, in the sound control panel, I've unchecked the boxes "'Play user interface sound effects' and 'Play feedback when the volume is changed?' When this failed to disable the sound, I executed the following terminal command: "defaults write sound "" -int 0", intended to terminate/prevent any and all system sounds.

The sound persists (both before and after) a full fresh (hard drive reformatted/partitioned) install of High Sierra 10.13.6 (the latest OS my iMac can run).

I wish I could describe it more effectively but the words that come to mind are that of a "digital plop".

The two attached screenshots list errors logged at the moment I heard the system event sound is generated.

The first screenshot illustrates a logged error timestamp of, continuing unbroken into the topmost timestamp on the second screenshot of A fresh EtreCheck report id attached.

1) How is it the iMac can generate an audible alert (at all), given preventative steps taken above?
2) Could the system sound be generated as a result of a "connection" or "pairing" between my iPhone 7 Plus, and the iMac? In other words, could there be a process, sourced from my iPhone, responsible for sound generation on my iMac? If so, how to identify and disrupt?

Can anyone help me diagnose and provide a solution?


  • Screen Shot 2020-05-12 at 5.24.08 PM.png
    Screen Shot 2020-05-12 at 5.24.08 PM.png
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  • Screen Shot 2020-05-12 at 5.24.26 PM.png
    Screen Shot 2020-05-12 at 5.24.26 PM.png
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  • EtreCheck Report 05-15-2020.pdf
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