If double-clicking doesn't work, you can drag/drop configurations onto the Tunnelblick icon in /Applications. In other words, open a Finder window showing /Applications, and drag/drop your configurations onto the Tunnelblick icon in that window.
Or you can Control-click the configuration and then select Open With… and select Tunnelblick. (By "Control-click" I mean hold down the Control key on the keyboard while you single-click the configuration. A context menu will appear with several choices.)
There are two things that I know of that cause double-clicking to not work:
- If you have other applications that are registered with OS X to respond to .ovpn (or .conf or .tblk) double-clicks, OS X may send the other application a message instead of sending it to Tunnelblick. This is probably the problem you have.
- There is a problem in OS X 10.11 (or maybe it showed up in 10.10, I don't remember) that causes double-clicks to sometimes not go to the most logical copy Tunnelblick. For example, when the Tunnelblick disk image is mounted (during a Tunnelblick installation, for example), sometimes OS X relaunches that Tunnelblick and sends it the double-click message, instead of sending it to the running Tunnelblick or the Tunnelblick in /Applications. There isn't anything that Tunnelblick can do to fix that OS X problem, except the most recent beta (3.6beta10) ejects the Tunnelblick disk image after installing Tunnelblick, so that the copy of Tunnelblick on the disk image won't be relaunched and sent the message. But if there are multiple copies of Tunnelblick available to OS X (if you copied it to the Desktop, for example), OS X may still find one and launch it and send it the double-click message, instead of sending it to the running Tunnelblick or the Tunnelblick in /Applications.