This error indicates that Tunnelblick was unable to load the kexts (drivers) required to make OpenVPN work.
The most common cause is that there are already VPN kexts loaded which conflict with the Tunnelblick OpenVPN kexts. The current Tunnelblick kexts are net.tunnelblick.tun or net.tunnelblick.tap
If you see either of the two errors listed at the top of the page in your Tunnelblick Log please do the following:
Go to Finder – Applications – Utilities
and press Enter
Copy the output, especially the very bottom as well as the log you obtained previously and email it to us.
If you wish to try and resolve this yourself scroll to the bottom of the kextstat output.
Look for any of the following
foo.tun or foo.tap – Obsolete Tunnelblick kexts
com.cisco.cscotun or com.cisco.cscotap – Cisco Any Connect SSL VPN kexts
com.viscosityvpn.Viscosity.tun or com.viscosityvpn.Viscosity.tap – Viscosity VPN client
Once you have found the problem kexts you can unload them as follows:
Go back to Terminal
Depending on which kext you are trying to unload based on the above kextstat report enter:
sudo kextunload -b com.cisco.cscotun and press Enter
sudo kextunload -b com.cisco.cscotap and press Enter
sudo kextunload -b foo.tun and press Enter
sudo kextunload -b foo.tap and press Enter
sudo kextunload -b com.viscosityvpn.Viscosity.tun and press Enter
sudo kextunload -b com.viscosityvpn.Viscosity.tap and press Enter
The Mac will request your password to allow for the removal.
This fix will likely be undone if you reboot the computer as the conflicting software will likely reload the kexts again.
The long term solution to this problem is to disable the conflicting program from launching at startup.