Virtual Device Serial0 Will Start Disconnected -
If your workflow requires an active virtual serial port (e.g., for kernel debugging, firmware development, or connecting legacy Cisco equipment), you must route the connection to a valid resource instead of a missing physical port. Open the virtual machine and select Serial Port .
Method 1: Remove the Serial Port (Recommended for Most Users)
The "virtual device serial0 will start disconnected" message is a benign configuration alert indicating a hardware mismatch between your virtual machine settings and your physical host machine.
If you are dealing with this warning across your virtual environment, tell me: virtual device serial0 will start disconnected
Open it in a text editor and search for all lines beginning with serial0. :
When powering on a virtual machine (VM) in VMware Workstation, VMware Fusion, or ESXi, you may encounter a pop-up warning stating:
While this error rarely prevents the guest operating system from booting, it introduces annoying startup delays and indicates a misconfiguration in your virtual hardware settings. If your workflow requires an active virtual serial port (e
Most users can safely ignore the warning, especially if they are not actively using the serial port. For those who find the message persistent and wish to eliminate it, identifying the root cause through the troubleshooting steps outlined above—focusing on virtual printing configuration, license validation, host port availability, VMX file integrity, and network or firewall settings—will lead to a clean, warning‑free boot every time.
To stop the warning while keeping the device available, change the startConnected value to false: serial0.startConnected = "FALSE" Use code with caution.
The warning triggers because the VM configuration includes a virtual serial port (COM port), but the hypervisor cannot map it to a valid physical backend. This happens for three primary reasons: If you are dealing with this warning across
"virtual device serial0 will start disconnected" is when you've enabled a serial port but not defined a live connection. It does not indicate a problem with your virtual machine or device.
Older enterprise software that relies on a serial connection for hardware dongles, automated machinery, or specialized modems will fail to function.
The VM will still boot, but the virtual serial port will not be functional. Why Is This Error Occurring? (Common Causes)