There are several OpenVPN clients for MacOS but the most popular one is Tunnelblick. At the time of writing the latest stable version is 3.2.8 but there is a red health warning saying that it’s not recommended for OS X 10.8 ("Mountain Lion"), where as the previous stable version 3.3beta21b version is. Yeh, weird that! Version 3.3beta21b had one problem with launching the VPN tunnel, it couldn’t find the configurations specified in the .opvn configuration file. First we’all go through how to install it and then how to get around the bug with launching it.

1. Your VPN administrator will have given you a zip file containing your OpenVPN configuration. It will have a name like yourname-12345.zip.
2. Finder will automatically unpack it and create a folder called yourname-12345
3. Go to Tunnelblick’s download page: http://code.google.com/p/tunnelblick/wiki/DownloadsEntry and download Tunnelblick 3.3beta21b.
4. Launch the download.
5. Double-click the Tunnelblick.app icon.
6. Click I have configuration files.
7. Click OpenVPN Configuration(s).
8. Click Open Private Configuration Folder.
9. The Finder will open.
10. Drag the youname-12345 configuration folder to the same place where you see the Launch Tunnelblick icon.
11. Click Done.
12. Click Do not check for a change.
13. Click Don’t check for automatic updates. The latest version is not compatible with Mountain Lion so we don’t want your Mac to automatically install it!

If you go up to the greyed out tunnel icon next to the time on the menu bar and click it you can select yourname-12345->Connect <VPN name>. It will pop up a message saying:

Warning! Tunnelblick was unable to start OpenVPN to connect yourname-12345/<VPN name>. For details, see the OpenVPN log in the VPN Details… window

Click the greyed out tunnel icon again and select VPN Details. For the sake of those people googling (searching) for a solution here is the error message from the log to bring you in!

2013-01-18 00:49:41 *Tunnelblick: OS X 10.6.8; Tunnelblick 3.3beta21b (build 3114.3185) 2013-01-18 00:49:41 *Tunnelblick: Attempting connection with yourname-12345/vpn-name; Set nameserver = 1; monitoring connection 2013-01-18 00:49:41 *Tunnelblick: /Applications/Tunnelblick.app/Contents/Resources/openvpnstart start yourname-12345/vpn-name.ovpn 1337 1 0 0 0 49 -atADGNWradsgnw 2013-01-18 00:49:42 *Tunnelblick: Could not start OpenVPN (openvpnstart returned with status #242) Contents of the openvpnstart log: OpenVPN returned with status 1, errno = 2: No such file or directory Command used to start OpenVPN (one argument per displayed line): /Applications/Tunnelblick.app/Contents/Resources/openvpn/openvpn-2.3-alpha1/openvpn –cd /Users/username/Library/Application Support/Tunnelblick/Configurations –daemon –management 127.0.0.1 1337 –config /Users/username/Library/Application Support/Tunnelblick/Configurations/yourname-12345/vpn-name.ovpn –log /Library/Application Support/Tunnelblick/Logs/-SUsers-Syourname-SLibrary-SApplication Support-STunnelblick-SConfigurations-Syourname-12345-Sclient–vpn-name.ovpn.1_0_0_0_49.1337.openvpn.log –management-query-passwords –management-hold –script-security 2 –up /Applications/Tunnelblick.app/Contents/Resources/client.up.tunnelblick.sh -m -w -d -atADGNWradsgnw –down /Applications/Tunnelblick.app/Contents/Resources/client.down.tunnelblick.sh -m -w -d -atADGNWradsgnw –up-restart –route-pre-down /Applications/Tunnelblick.app/Contents/Resources/client.route-pre-down.tunnelblick.sh -m -w -d -atADGNWradsgnw Contents of the OpenVPN log: Options error: –ca fails with ‘ca.crt’: No such file or directory Options error: –cert fails with ‘yourname-12345.crt’: No such file or directory Options error: –key fails with ‘yourname-12345.key’: No such file or directory Options error: Please correct these errors. Use –help for more information. More details may be in the Console Log’s “All Messages”

Now the fix.

1. Open a Finder window and go to: /Users/username/Library/Application Support/Tunnelblick/Configurations/yourname-12345
2. Edit the file vpn-name.ovpn
3. At the bottom of the file you will see the following lines:

   ca ca.crt key yourname-12345.key cert yourname-12345.crt

4. The launcher was complaining that it couldn’t find the files so there is something wrong with how the software is working out which directory to look in.
5. You must change the lines to include the full path to the file.

   ca “/Users/username/Library/Application Support/Tunnelblick/Configurations/yourname-12345/ca.crt” key “/Users/username/Library/Application Support/Tunnelblick/Configurations/yourname-12345/yourname-12345.key” cert “/Users/username/Library/Application Support/Tunnelblick/Configurations/yourname-12345/yourname-12345.crt”

6. After the change, it doesn’t matter what the application thinks is the configuration directory as we are using the absolute path to the files instead of a relative one.
7. Go up to the greyed out tunnel icon and select yourname-12345->Connect <VPN name>.
8. And hay presto, you’re in.