Virtual Device Serial0 Will Start Disconnected [new] Jun 2026
QEMU scenario:
You can connect to serial0 post-launch using one of the following methods:
The "virtual device serial0 will start disconnected" warning is a harmless artifact of legacy hardware configurations or automated P2V migrations. While it poses no threat to modern guest operating systems, maintaining clean environment logs is a hallmark of good system administration. Removing the unneeded virtual serial port through your hypervisor's settings panel or changing the startConnected attribute to FALSE in the configuration file will clear the error, leaving your system logs pristine and easier to audit. virtual device serial0 will start disconnected
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.
If you cannot delete the device because you might need it later, you can tell VMware to ignore its connection state during the boot sequence. This eliminates the startup warning popup. Open your virtual machine's . Select the Serial Port from the hardware list. On the right-hand panel, locate the Device status section. Uncheck the box next to Connect at power on . Uncheck Connected if it is currently selected. Click OK to apply changes. QEMU scenario: You can connect to serial0 post-launch
Ensure the box is checked only if the target file or pipe is configured correctly. Click OK to commit the settings. Fixing the Error via the .VMX Configuration File
Even after you connect the virtual cable, you might still face a down/down or up/down status. After fixing the "start disconnected" message, ensure you have a set on the DCE side. On some server boards, BIOS features like Serial
Another application on your host computer is already using the physical serial port or file resource, locking VMware out.
The VMware error message is a common warning that appears when powering on a virtual machine (VM) in VMware Workstation, Player, or ESXi. While it usually does not prevent the guest operating system from booting, it indicates a configuration mismatch between the virtual hardware settings and the physical host machine.
Developers who utilize virtual serial ports to capture low-level OS kernel debugging data across a virtual network or file output will lose their data stream.
Scroll down the virtual hardware list until you locate .