Won't Stay in 64-bit Mode...

I just got around to upgrading to Snow Leopard, (I know-late to the party). My MacBook won't go into 64-bit mode let alone stay there. I tried logging in as the Root Admin and trying the terminal line trick so that it always boots to 64...no luck there. Every time I reboot and check "about this Mac" in the software section is says 64-bit kernel and extentions: NO

Any advice?

Unibody MacBook 5,1 2.4GHz Core 2 Duo

all up to date on software and firmware. I have 8 gigs of RAM on order, not that it much now but beats buying a new laptop right now.

Snow Leopard is designed to boot into 32 bit mode, however, it will run those apps designed for 64 bit mode as 64 bit apps. You can hold down the 6 and 4 keys as you boot and that will put Snow Leopard in 64 bit mode but as soon as you reboot, it will default back to 32 bit.

If you want your OS to remain in 64 bit mode all the time, switch to Lion.

sorry to hijack the thread - does that mean that Lion defaults to 64 bit mode?

I donno, I did set my MBP (Same as yours) to boot with 64bit while I was still on Snow Leopard and it worked fine even with reboots.

louishen said:

sorry to hijack the thread - does that mean that Lion defaults to 64 bit mode?

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As far as I know, yes. I have several "Other" preference panels that only work in 32 bit mode. Whenever I invoke one, Lion tells me it will have to reboot System Preferences and open it in 32 bit mode.

Also, Lion requires a 64 bit capable CPU before it will install. (Core 2 Duo or better.)

I donno, I did set my MBP (Same as yours) to boot with 64bit while I was still on Snow Leopard and it worked fine even with reboots.

Click to expand...

Note - the OP is using a Uni body MacBook not MBP.

The terminal commands you show should keep it in 64 bit mode. I don't know if those are what the OP used though. However, booting with the 6 and 4 keys held down is a one time shot only.

uname -a would imply that I am running an x86 version of Lion:

~ :: uname -a
Darwin Illuminatis-MacBook.local 11.1.0 Darwin Kernel Version 11.1.0: Tue Jul 26 16:09:02 PDT 2011; root:xnu-1699.22.81~1/RELEASE_I386 i386

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A look at kernel-task in Activity Monitor will also show that it isn't a 64-bit app. So, it would seem that Apple is continuing the slow march to full 64-bit support.

(Yes, my Mac is called Illuminatis-MacBook - don't let that secret out).

Thank You's to the responses. Sure enough vansmith...looked in Activity Monitor and it is showing 64-bit...even after a few reboots for software updates.