Start Disconnected | Virtual Device Serial0 Will

When setting up network‑backed serial ports or named pipes, add and test each component one at a time. Verify connectivity on the host side before powering on the VM.

[[defaults]] console = 2000 sparsemem = True ghostios = True # This does not suppress the message, but ensures faster boot

The fluorescent lights of the server room hummed a low, mocking C-sharp as Elias stared at the monitor. It was 3:04 AM. On the screen, a small, persistent dialogue box glowed like a digital taunt:

The resolution depends on your specific needs and configuration:

If the UI options do not fix the issue, you may need to edit the VM's configuration file directly. virtual device serial0 will start disconnected

A: Look for associated messages in the VM log. The presence of "virtual printing feature is globally disabled" points to ThinPrint as the cause. A licensing error message in ESXi indicates a license limitation. An access‑denied error suggests a host serial port permission issue. If the warning appears alone with no other messages, examine your serial port configuration in the VM settings.

For a serial link to function, one side must be a DCE (Data Circuit-terminating Equipment) and the other a DTE (Data Terminal Equipment). The DCE side is responsible for providing the clocking signal to the DTE side. In a lab environment, when two routers are connected back-to-back with a serial cable, one router must act as the DCE. If the DCE side is not configured with a clock rate , the line protocol will remain down. You can determine which role an interface is playing using the show controllers serial0 command.

In VMware environments, serial0 refers to the first virtual serial (COM) port configured for a virtual machine. The message indicates that VMware cannot establish a connection for this virtual serial port when the VM boots up, so the port will start in a disconnected state. Once inside the guest operating system, the serial port will be unavailable unless it is manually reconnected or the underlying issue is addressed.

. If the printer is not needed, you can remove the device entirely. Edit the .vmx File When setting up network‑backed serial ports or named

The error message "Virtual device serial0 will start disconnected" typically occurs in

Under the "Device status" section, uncheck .

Completely power off the affected virtual machine (do not just suspend it).

The serial port is configured to log output to a text file (e.g., serial.log ), but the destination path is invalid, read-only, or locked by another process. It was 3:04 AM

To help narrow down the exact steps for your setup, let me know:

Depending on whether you actually need the serial port or just want the error to go away, use one of the following three methods. Method 1: Remove the Serial Port (Recommended)

. This issue is most frequently tied to deprecated printing features or misconfigured virtual machine (VM) settings. Core Causes ThinPrint Deprecation : In recent versions like VMware Workstation 17.5 Fusion 13.5

The error indicates that your VM is configured to look for a serial (COM) port on your physical computer, but it can’t find one to "handshake" with. Because the VM can't establish this link, it simply starts with that specific virtual device disabled. Common Causes The "ThinPrint" Legacy:

: In Proxmox (a Debian-based virtualization platform), VMs run under QEMU. The "Virtual device serial0 will start disconnected" warning appears with the same meaning as in VMware—it's informing you that the VM is configured with a serial console that is not currently attached to any file or physical port. It is a normal message for VMs where the serial port is not in use but is present in the configuration.