- 05
- May
The Problem:
After installing Cisco’s Mac VPN Client and launching the application, you get the message:
Error 51: Unable to communicate with the VPN subsystem. Please make sure that you have at least one network interface that is currently active and has an IP address and start this application again.
The Solution:
If you just bought a new MacBook Pro (17-inch, Early 2011), MacBook Pro (15-inch, Early 2011), MacBook Pro (13-inch, Early 2011), or Mac Pro (Mid 2010), your system will – by default – load with Apple’s 64-bit kernel (Apple 1). This prevents you from launching certain 32-bit applications. In order to use your VPN, you will have to switch your boot kernel to 32-bit:
Switch to the 32-bit Kernel (Download Script)
1. Open Terminal (Applications/Utilities/Terminal)
2. Switch to the 32-bit kernel by typing the following command:
sudo systemsetup -setkernelbootarchitecture i386
3. Reboot your system and you will be using the 32-bit kernel, your VPN client will work now.
If you would like to take advantage of your 64-bit capabilities after switching to the 32-bit kernel, you will have to switch back to the 64-bit kernel:
Switch to the 64-bit Kernel (Download Script)
1. Open Terminal (Applications/Utilities/Terminal)
2. Switch to the 64-bit kernel by typing the following command:
sudo systemsetup -setkernelbootarchitecture x86_64
3. Reboot your system and you will be using the 64-bit kernel.
You can also select which boot kernel to use at start-up – much like an option boot.
Selecting Kernel on Boot
1. If your Mac is set to boot the 32-bit kernel by default (you have modified it per the instructions above), holding the “6″ and “4″ keys at start-up will boot the 64-bit kernel.
2. If your Mac is set to boot the 64-bit kernel by default (factory settings for the systems listed above), holding the “3″ and “2″ keys at start-up will boot the 32-bit kernel.
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