I need to install OpenVPN (using the latest stable, OpenVPN 2.2.1) on a Windows 2008 Server R2. All works fine, except I can't seem to install the TAP adapter. Running
addtap.bat (as administrator even with explicit "run as administrator") or re-installing OpenVPN does not produce any errors, but running OpenVPN fails: "CreateFile failed on TAP device" and "All TAP-Win32 adapters on this system are currently in use."
Looking into Window's hardware manager shows the TAP adapter with a warning symbol, status: "The driver hasn't been installed because it produces errors with Windows; you must restart your computer." (freely translated from German) Now, after rebooting, the TAP adapter is GONE completely!
Need urgent help, any input appreciated! Thanks!