Virtual Device Serial0 Will Start Disconnected _best_
If you are running ESXi and the warning appears alongside a license restriction, check your current vSphere license:
If you’ve recently powered on a VMware Workstation or ESXi virtual machine only to be greeted by the warning message you aren’t alone. This is a common configuration hiccup that occurs when a VM is looking for a physical or virtual serial (COM) port that the host system can’t provide.
If you might need the serial port in the future but want to suppress the boot-time error message, you can tell VMware not to connect it automatically.
The warning carries unique implications in different operational contexts.
: The guest OS may be attempting to allocate the virtual device to a COM port that is already in use by the host system or another process. Licensing Restrictions virtual device serial0 will start disconnected
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)
On some server boards, BIOS features like Serial over LAN or Console Redirection may reserve the physical COM port for the host firmware. Disable these features in BIOS to free the port for VMware.
Setting up a virtual serial console allows text-based redirection for Linux servers or network appliances.
Do you actually (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 If you are running ESXi and the warning
He’d checked the .vmx files. He’d tried to force the connection, adding serial0.present = "TRUE" and serial0.startConnected = "TRUE" until his fingers went numb. But the hypervisor was stubborn. It knew there was no physical serial port on the sleek, modern host machine. It refused to bridge a gap that spanned thirty years of hardware evolution. "Just let me in," Elias whispered to the glass.
Since the most common cause is the deprecated ThinPrint service, removing the virtual printer often stops the message. 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
When powering on a virtual machine (VM) in VMware Workstation or ESXi, you might encounter a persistent warning message:
If you no longer need the virtual serial port, set serial0.present = "FALSE" or remove all serial0.* lines entirely. Method 1: Remove the Serial Port (Recommended) On
: 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.
Let’s fix the interface so that it starts connected. The solution depends entirely on your lab environment.
Serial logging is a lifesaver when diagnosing early boot failures. vSphere supports a Virtual Serial Port Concentrator (vSPC) that allows a VM to log directly to a serial console server, just like a physical server. When capturing ESXi PSOD (purple screen of death) information, configuring a virtual serial port to output to a file on a datastore ensures that crash logs are not lost even when the guest cannot write to its own disk. In such setups, the "will start disconnected" message often indicates that the log file could not be opened; the solution is to verify write permissions on the datastore and ensure the serial port is configured to rather than replace the file.