Virtual Device Serial0 Will Start Disconnected -

If you unchecked "Connect at power on" but still get the message:

This message typically appears in virtual machine platforms (like VMware, VirtualBox, or QEMU) or network simulation tools (like GNS3 or EVE-NG).

Troubleshooting VMware: "Virtual device serial0 will start disconnected"

If you’ve recently powered on a VMware Virtual Machine (VM) only to be greeted by the message "Virtual device serial0 will start disconnected," you aren’t alone. While this warning might seem alarming, it’s usually a minor configuration mismatch rather than a sign of a failing system.

Here is a deep dive into why this happens and how you can fix it. Why Does This Message Appear?

In the world of virtualization, "Serial0" refers to a virtual serial (COM) port assigned to your VM. This error occurs because the VM is configured to look for a physical or virtual serial port on the host machine that either doesn't exist or is currently in use by another application. Common scenarios include:

Legacy Templates: You are using a VM template that originally had a serial port mapped for debugging.

Hardware Migration: You moved the VM from a host that had a physical COM port to one that doesn't.

Disconnected Peripherals: The VM is set to connect to a named pipe or a physical port that is disconnected. How to Fix the "Serial0" Warning virtual device serial0 will start disconnected

Depending on whether you actually need the serial port, there are two main ways to handle this. Method 1: Remove the Serial Port (Recommended)

Most modern users and operating systems do not require a serial port. Removing it is the cleanest way to stop the error message. Shut down the Virtual Machine.

Right-click the VM in your library and select Edit Settings. 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 error message "Virtual device serial0 will start disconnected" in VMware (Workstation or Fusion) most commonly occurs because support for ThinPrint (virtual printing) has been discontinued in recent versions like Workstation 17.5 and Fusion 13.5. Primary Fixes Remove the Printer Device (Easiest Method): Shut down the virtual machine. Go to VM Settings > Hardware tab. Select the Printer device and click Remove. Click OK and restart the VM.

Edit the .vmx Configuration File (Advanced):If the device isn't visible in the GUI or the message persists, you can manually remove the offending lines from your VM's configuration file: Open your VM's folder and locate the .vmx file. Open it with a text editor (like Notepad or TextEdit). Find and delete the following lines: serial0.fileType = "thinprint" serial0.fileName = "thinprint" serial0.present = "TRUE" Save and close the file, then restart your VM. Troubleshooting Physical Port Conflicts

If you actually need to use a serial port and the error says "no corresponding device available on the host," try these steps:

Verify Host COM Port: Ensure the serial port (e.g., COM1 or /dev/ttyS0) is enabled in your host's BIOS and is not being used by another application (like Putty).

Manual Mapping: Manually edit the .vmx file to point to the correct host port by changing the serial0.fileName to the specific port name, such as COM3 on Windows or /dev/tty.USA19H3d2P1.1 on Mac. If you unchecked "Connect at power on" but

For more detailed guides, you can visit the Broadcom/VMware Knowledge Base or the VMware Fusion community discussions. If you’d like, let me know:

Which VMware product and version you are using (e.g., Workstation 17.5)?

Do you actually need to use a serial device (like a console cable), or do you just want the error to go away? I can provide the exact steps for your specific version. USB Serial Port kinda working | Fusion - Broadcom Community

The error message "virtual device serial0 will start disconnected" typically appears in VMware environments when a virtual machine (VM) is configured with a serial port that it cannot properly initialize at startup. This is often a non-critical notification rather than a fatal error, but it can be annoying or indicate a configuration mismatch. Why This Happens

Virtual Printing Conflict: A common cause is the "Virtual Printing" feature. If this feature is globally disabled on your host system but enabled in the VM settings, VMware attempts to use serial0 for the printer connection and fails, triggering the message.

Missing Physical Hardware: The VM might be configured to connect to a physical serial port (COM1, etc.) on the host that doesn't exist or is currently being used by another application.

Manual VMX Edits: If you have manually edited the .vmx file to add a serial port but haven't correctly defined the pipe or file it should connect to, the device will remain disconnected. How to Fix It 1. Disable the Serial Port (If Not Needed)

If you aren't intentionally using a serial device or virtual printer: Shut down the Virtual Machine. Restart the router

Go to VM > Settings (or right-click the VM in the library and select Settings). Select Serial Port from the Hardware tab.

Uncheck Connect at power on or simply click Remove to delete the device entirely. 2. Resolve Virtual Printing Issues If the message specifically mentions virtual printing: In the VM Settings, look for the Printer device.

If you don't need to print from the VM, Remove the Printer device.

Alternatively, go to Edit > Preferences in the VMware Workstation/Player menu, navigate to Devices, and ensure "Enable virtual printers" is checked if you do want to use this feature. 3. Adjust the .vmx Configuration

For advanced users needing the port to start connected (e.g., for debugging or specific hardware mapping), ensure these lines exist in your .vmx file: serial0.present = "TRUE" serial0.startConnected = "TRUE"

Ensure the serial0.fileType matches your intent (e.g., "device", "pipe", or "file"). USB Serial Port kinda working | Fusion - Broadcom Community

This warning message (or log entry) typically appears in VMware products (like VMware Workstation, Player, or ESXi). It indicates that the virtual machine is configured to have a serial port, but the host computer cannot connect to it—usually because the designated file or device path does not exist yet.

Here is a comprehensive guide on why this happens and how to resolve it.

Some VM templates or quick-creation wizards add a serial port by default but leave it disconnected. This is common in Linux VM templates that include a legacy console serial port that may not be needed.