Virtual Device Serial0 Will Start Disconnected !exclusive! Now

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.

This warning message, , is one of the most common errors seen by users of VMware Workstation, VMware Player, and VMware Fusion. virtual device serial0 will start disconnected

The "serial0" port was the only way into the legacy kernel of the "Sentinel" project—a massive, decades-old encryption engine the company had bought for pennies and now couldn’t crack. Without that virtual serial connection, the kernel stayed isolated in its own private, silent void. If you’ve recently powered on a VMware Workstation

: For developers using platforms like an mbed LPC1768, this message can indicate a driver conflict. The host may have old drivers installed, or the current drivers are failing to start, leading to the serial device being disconnected. The "serial0" port was the only way into

Developing operating system kernels or drivers where a serial connection is required to output debug logs from the guest to a host debugger (like WinDbg).