Can't install tap driver using tapinstall.exe for OpenVPN when run from a .bat file, but it works when running OpenVPN installer

Solution 1:

I had a similar problem, and googling around found some potential solutions.

The simplest is to check whether the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce (HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\RunOnce for Win 7 64 bit) registry key exists, and add it if it does not.

There is a registry problem which is related to using ESET Smart Security; you can find the description here.

The one that worked for me was dropping the OpenVPN-provided TAP driver altogether, and using http://openvpn.se/files/xp64/tap-win64.zip (Which is unsigned, so if you want it to work on Win7, you will need to sign it - here is a tutorial on how to self-sign it. I only needed it to work on my own machine so I just set tapistall.exe into Vista compatibility mode.)