When a virtual machine starts with the warning "Virtual device serial0 will start disconnected," it typically means the VM is trying to initialize a serial port that is either misconfigured, pointing to a non-existent physical resource, or linked to a legacy feature that is no longer supported. Core Causes of the Warning
ThinPrint Feature Removal: The most common reason in modern versions of VMware Workstation (17.5+) and VMware Fusion (13.5+) is the removal of the ThinPrint virtual printing feature. These newer versions no longer support the ThinPrint protocol, which often utilized serial0.
Missing Host Resources: The VM configuration might be set to map serial0 to a physical COM port on the host machine that is currently in use by another application or simply does not exist.
Disconnected on Power On: The "Connect at power on" option for the serial device may be unchecked in the VM settings, triggering a notification that it will remain inactive. How to Resolve the Warning
Depending on your needs, you can either remove the device entirely or reconfigure it to clear the error. Option 1: Remove the Printer Device (Recommended)
If you do not explicitly use virtual printing, removing the legacy device is the cleanest fix. Power off the virtual machine completely. Open Edit Virtual Machine Settings.
Select the Printer or Serial Port device associated with serial0. Click Remove and save the changes. Option 2: Edit the VMX Configuration File
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.
Locate your VM's folder and open the .vmx file with a text editor. Find and delete the following lines if they exist: serial0.fileType = "thinprint" serial0.fileName = "thinprint" serial0.present = "TRUE" Save the file and restart the VM. Option 3: Disable "Connect at Power On"
If you want to keep the device but stop the warning, you can tell VMware not to attempt a connection during boot.
In the VM settings, go to the Serial Port section and uncheck Connect at power on. This will stop the system from checking for the resource every time it starts. Why this happens with Printers
Legacy VMware versions automatically added a virtual printer that used a virtual serial port to communicate with host drivers. Because Broadcom/VMware discontinued ThinPrint, the software identifies a device it can no longer operate, resulting in the "start disconnected" status. AI responses may include mistakes. Learn more VMware Cannot Connect the Virtual Device sata0:1 Error
This message typically appears in VMware Workstation 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 virtual device serial0 will start disconnected
Legacy "ThinPrint" Service: Recent versions of VMware (Workstation 17.5+ and Fusion 13.5+) have removed the ThinPrint virtual printing feature. If your VM was created in an older version, it might still try to initialize a virtual serial port (serial0) specifically for this printer service.
Missing Physical Hardware: The VM is set to connect to a physical COM port on your host machine that does not exist or is currently being used by another application.
Invalid Configuration: The .vmx configuration file contains parameters for serial0 that the hypervisor cannot process, such as an invalid file type or destination. How to Fix It Method 1: Disable Virtual Printing (Recommended)
Since the most common cause is the deprecated ThinPrint service, removing the virtual printer often stops the message. Shut down the virtual machine. Go to Virtual Machine Settings. Look for Virtual Printer in the device list. Select it and click Remove. Restart the VM to see if the message persists. Method 2: Manually Edit the .vmx File
If the device doesn't appear in the standard settings menu, you can remove it directly from the configuration file. Shut down the VM and close VMware.
Navigate to the folder where your VM is stored and locate the .vmx file. Open it with a text editor (like Notepad).
Search for lines starting with serial0 and either delete them or change their values to FALSE: serial0.present = "FALSE"
Remove lines like serial0.fileType = "thinprint" and serial0.fileName = "thinprint". Save the file and restart VMware. Method 3: Reconfigure the Serial Port
If you actually need a serial port (e.g., for debugging), ensure it is mapped to a valid resource. Go to Edit Settings > Serial Port.
Ensure it is mapped to a valid Physical serial port, Output file, or Named pipe.
If you aren't using it, simply uncheck Connect at power on to hide the warning while keeping the device in your configuration.
Virtual Device Serial0 Will Start Disconnected - Google Groups When a virtual machine starts with the warning
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.
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, "virtual device serial0 will start disconnected", is one of the most common errors seen by users of VMware Workstation, VMware Player, and VMware Fusion. Step 3: Change the Connection State Option A:
It typically appears as a pop-up window immediately after you power on a virtual machine (VM). While it often looks like a critical error, it is usually just a configuration notification.
Here is your complete guide to understanding, fixing, and silencing this message.
Option A: Remove the Serial Port (if unused)
Option B: Configure it to Connect at Power On
If you want the port active but connected to nothing (to suppress the warning), you must trick VMware into thinking it has a valid backing:
nul (Windows) or /dev/null (Linux/macOS).The VM will now think it has a valid serial port and will not log the disconnected warning.
Option C: Use Named Pipe to Nowhere (Advanced)
\\.\pipe\fake_serial (Windows) or /tmp/fake_serial (Linux).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:
A student attempted to build a Frame Relay switch using a Cisco 3640 in GNS3. After configuring the Frame Relay map statements and inverse ARP, the PVCs remained inactive. The student spent six hours checking DLCI numbers and encapsulation types.
The root cause? The console log from boot clearly showed: "Virtual device serial0 will start disconnected" and "Virtual device serial1 will start disconnected". The student had never connected the cables from the router to the Frame Relay switch.
Moral of the story: Always read the console boot messages. That "disconnected" line is not a warning; it is a direct status report.