For advanced users or situations where the GUI does not show the device (common in Fusion or Workstation updates), you can manually remove the entries from the .vmx file.

This message typically appears in or VMware Fusion when a virtual machine (VM) is configured to look for a serial port that is unavailable, invalid, or belongs to a legacy feature no longer supported. Why it Happens

You have a Serial Port added to your VM settings, but your actual laptop or desktop doesn't have a physical COM port. Conflict with Host Drivers:

Network‑backed serial ports require careful firewall management, especially in ESXi. Before connecting a network‑backed serial port, add the proper firewall rule sets to prevent the ESXi firewall from blocking the connection: use VM serial port connected to vSPC when using the Virtual Serial Port Concentrator, or VM serial port connected over network for direct TCP connections. The default vSPC port is 9977, and outgoing TCP ports should range from 1024 upward.

Method 3: Change the Serial Port Connection Type (For Advanced Users)

By understanding what this message means and when it requires action, system administrators can focus their efforts on truly critical issues while maintaining a healthy, efficient virtualized environment.

Most modern operating systems (Windows 10/11, standard Linux distros) do not require a serial port to function. If you aren't doing low-level kernel debugging or connecting to industrial hardware, the easiest fix is to delete the device. the virtual machine. Right-click the VM and select Settings . Go to the Hardware tab. Locate Serial Port (or Serial0) in the list. Click Remove . Click OK and restart the VM. Method 2: Disconnect at Power On

Shut down the virtual machine and close your VMware application.