Right-click the VM in your library and select . Locate Serial Port 1 (or Serial0) in the hardware list. Click the Remove or "X" icon. Click OK and power the VM back on.
The VM is set to connect to a named pipe or a physical port that is disconnected. How to Fix the "Serial0" Warning
Here is a deep dive into why this happens and how you can fix it. Why Does This Message Appear?
