Virtual Device Serial0 Will Start Disconnected 〈90% PREMIUM〉

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

Breakdown of the Terms:

  • Virtual Device – A piece of emulated hardware inside the VM (e.g., a network adapter, disk drive, or serial port).
  • serial0 – The first virtual serial port (COM1 in Windows, /dev/ttyS0 in Linux).
  • Will start disconnected – VMware will not attempt to link this virtual port to any physical or file-backed resource at boot.

When to worry

  • You expect console access (guest serial console, dmesg early-boot, emergency shell) but cannot connect.
  • Services that rely on serial communication inside the guest are failing.
  • There are follow-up error messages about failing to create backend (permissions, path missing).

Scenario C: The message persists even after fixing it

If you unchecked "Connect at power on" but still get the message: virtual device serial0 will start disconnected

  1. You might have multiple serial ports. Check the VM Settings for serial1, serial2, etc., and remove them too.
  2. Check for a prefs.ini file in your VMware installation folder or your user documents folder (%AppData%\VMware on Windows). Sometimes global preferences force a connection.