What is the Cisco VPN Client error message "Required VPN subsystem not available" When starting up the VPN client software, I get the following error message: “Required VPN subsystem not available”. Why? There are several possible reasons why this happened; most likely tied to the Cisco VPN Service. A lot of times I’ve seen this happen because the VPN service starts up before any working networking connection has started. Try the following steps: 1. Restart the Service a) Make sure you have a working network connection. If you are using the wireless UCLAWLAN , see if you can reach any UCLA website like http://www.bol.ucla.edu . If you are using a wired connection, see if you can reach any website like http://www.google.com b) Restart the Cisco VPN Service. Click Start → Run… → type in “services.msc” → Right-Click on “Cisco Systems, Inc. VPN Service” → select “Restart” 2. Reboot the Machine 3. Un-install and re-install the VPN service