Here’s a useful write-up on the , covering what it is, how it works, common use cases, and troubleshooting tips. What Is the Tap-Windows Adapter V9? The Tap-Windows Adapter V9 is a virtual network kernel driver for Windows. It’s part of the TAP (Tunnel Adapter) framework, originally from the VDE (Virtual Distributed Ethernet) project and widely distributed with OpenVPN , VPN clients , and virtualization software .