[SOLVED] Ubuntu 20.04 creates a file "serial.txt" on my macOS Desktop

For some reason, each time I start my Ubuntu 20.04 VM, a file "serial.txt" is written to my desktop. It's a blank file. I don't know what it's for. I can delete it, but it comes back each time.

The file is not created when starting Ubuntu 18.04. It's not created when starting Windows 10, just Ubuntu 20.04 does this.

I'm on Big Sur running Parallels 16 Pro.

 

Probably it is created by the virtual serial port.
Try to disable it here:

 

Thank you! I had set this up while troubleshooting a serial port, but I was confused by the name, though it was something else, such as a serial number or product key. That's fantastic.