On 31/03/2021 20:31, Roger Mills wrote:
My W10/64 Pro desktop computer emits a strange squawking noise from time
to time - typically several times a day but sometimes several times in
quick succession.

Each instance is short and sharp, and lasts about 300mS. It is
definitely coming through the audio system rather than being (say) a
disk bearing because its volume depends on the volume control setting,
and I have been able to record it by setting the recording input as
"Stereo Mix".

You can hear it he
https://app.box.com/s/0gtq2lg1eti3z3xfiw898i2b65piq6sp and you can see
the waveform he
https://app.box.com/s/2tewwkwnlqb8uiwiq9glz101rvg4pc4b

I assume that some application or other is trying to tell me something,
but it's never accompanied by any message or notification on the screen,
and I can't find anything in the error logs. In addition, I can't find
any system sound which sounds like this.

I shall be most grateful if someone can put me put me out of my misery
and tell me what's likely to be causing it.

It's looking for passing submarines.

Sorry. It's not a sound that I recognise as a normal PC notification.