Is it normal for 2018 Mac Mini to make screetchy noises? I have just purchased a new 2018 Mac Mini with a SSD drive.

Sometimes when reading or writing, it makes a quite screetchy noise. It's not loud, but however it's quite sharp which made me cautious.

I was under the impression that SSD's don't make any particular noises. I have a MacBook Pro Late-2017 with a SSD, and I never hear it make any noises when read/writing.

Please have a listen to the audio file below. Note that the microphone is close to the computer, so the fan and screetch noise is relatively loud in the clip. In reality, it's noticeable but quite muted. Most of the screetch noise is heard in the beginning.

https://vocaroo.com/i/s1piq8nQW12V

Perhaps it's not even the SSD making these noises?
If it's a "screechy" noise as you describe the it's very possible it could be either "capacitor squeal or coil whine."

In the audio recording, the fan itself was generating a good deal of (normal) noise so it was difficult to separate the two.  One way to determine if  it is the fan or not is to remove the back cover and stop the fan with your finger while listening for the noise.  If it goes away, it's the fan, if not, it's the logic board or power supply.

However, given that this is basically a brand new Mac mini, I would take it in for service even if it's just to get the problem logged.