Following on from Are the new Macbook Pro 64-bit or 32-bit?. The new MacBook Pros (March 2011) now seem to start in 64bit mode rather than 32bit mode. Thanks for letting us know Apple!
This is causing us a problem with our Cisco VPN client as it uses a 32bit kernel extension that naturally doesn't work when booted into 64bit mode.
Holding down 3 & 2 will start the machine into 32bit mode and the VPN client works fine, but when we reboot the Mac it starts up again into 64bit mode.
How can we ensure that the Macs start in 32bit mode.
(Sure getting a 64bit Cisco VPN client is a better solution…one day)
Best Answer
http://support.apple.com/kb/ht3773
To select the 32-bit kernel for the current startup disk, use the following command in Terminal:
sudo systemsetup -setkernelbootarchitecture i386