Virtual Device Serial0 Will Start Disconnected ^new^ 【DELUXE – 2027】

If you actually need the serial port for kernel debugging or specialized hardware, ensure the backing connection is correct.

The warning is completely harmless.

If serial0 is configured to use a named pipe or a TCP network socket, VMware must successfully create or connect to that endpoint. If the pipe name is incorrect, the server process is not listening, the TCP port is blocked, or the firewall is interfering, the connection fails. For example, VMware Fusion users have reported: "Virtual device serial0: File … exists, but no server is listening to it" . In network configurations, ensuring the correct firewall rule set is added in ESXi is critical. virtual device serial0 will start disconnected

If you are building massive topologies (e.g., 50+ routers for CCIE studies), seeing "virtual device serial0 will start disconnected" for every single router can clutter your console logs. Here is how to mute or manage it:

When a software like VMware or GNS3 powers on a virtual machine, it attempts to establish a connection for all virtual hardware. The message appears when it cannot find or open the specific device or file assigned to that serial port, so the virtual device will remain in a "disconnected" state. It is frequently accompanied by a related message: The virtual printing feature is globally disabled on this system . If you actually need the serial port for

A common mistake is logging into the router and typing:

The message indicates that the virtual device associated with serial0 (the first virtual serial port in many virtualization platforms) is not connected when the VM starts up. This disconnection can occur for several reasons: If the pipe name is incorrect, the server

This comprehensive article explains exactly what this message means, why it appears, when it is a problem, and how to fix or suppress it.