Q: OSX Lion: 64-bit Kernel and Extensions NO

Lion "About this Mac" telles you whether you are running 64/32 bit mode (I don't use Lion)?

Did you reboot?

What does this display in terminal:

uname -a

Also what does System Profiler say when you click Software for "64-bit Kernel and Extensions"?  (Maybe that's what you meant by About This Mac, i.e., opening System Profiler through there.)

"About This Mac" doesn't display that data for Lion.

To verify that you are running 64 bit, open activity

monitor and find kernel task.  The last column should

read "Intel(64 bit)" if it is in 64 bit mode.

Actually for Lion, the default for installation is 64 bit booting.

Do you really have a need for a 64-bit kernel?  I'm only asking because most people do not notice any differences between 32 or 64 bit kernels, as all your 64-bit apps can run with either kernel booted.

Can you boot into the 64-bit kernel holding the 6 and 4 keys during boot?

in-d wrote:

 

local 11.3.0 Darwin Kernel Version 11.3.0: Thu Jan 12 18:48:32 PST 2012; root:xnu-1699.24.23~1/RELEASE_I386 i386

Hmm, that is definitely 32-bit!

And you are saying if you boot into Snow Leopard that a uname -a will say x86_64?

Well at least they're consistent.  I thought you said SL was running in 64-bit which I couldn't really understand if the other wasn't.

What exact model of machine are you running -- year, version (for example I have a 2010 mac pro 5,1)?

Use your System Profiler in Utilities or Apple menu --> About This Mac --> More Info.  Click Hardware on the left and look at Hardware Overview on the right.  Look at Model Identifier.  For me is says MacPro5,1.  If you at least post the Model Identifier I could use MacTracker to hunt down the info on your model.