Model A1174 with 2 GHz Core Duo or Model A1207 with 2.16 or 2.33 GHz Core 2 Duo

271 Questions View all

Mountain Lion will not install on Core 2 Duo iMac

I have just upgraded my iMac 20" to a Core 2 Duo and everything is running fine.

I have then tried to upgrade from 10.6.8 to the new Mountain Lion, however I am getting a message that my machine is not compatible with Mountain Lion.

I really need to upgrade as I have to run the latest XCode environment.

The generalities of the Apple site does not explain exactly why the machine is not suitable. I did think it was a Core Duo vs Core 2 Duo thing.

Would appreciate any thoughts on how I can get this machine upgraded.

thanks

Answered! View the answer I have this problem too

Is this a good question?

Score 2
Add a comment
Deck the Halls
With tools and Fix Kits

2 Answers

Chosen Solution

Here's the spec's aside from processor there's memory, free space and an 800 MHz system bus, apparently the earlier non-AL iMacs lack. Of course you ran Apple update for EFI/Firmware updates to your custom updated machine.

Don't know how much you've stuck into this machine so far, but at a certain point you have know when to stop throwing good money after bad... It's like you're trying to run a 600HP Hemi in a family sedan... there's just too many gremlins in the mix. See if you can run 10.7.4 if you can stop there and sell it. Take the money and put it towards a new machine... or an older MacPro.

If this answer was helpful please remember to return and mark it Accepted.

Was this answer helpful?

Score 0
Add a comment
Most Helpful Answer

A data point that might be useful to others: I was poking around installer the Mountain Lion Installer a while back, and I found an interesting document: PlatformSupport.plist, which lists the board ID codes and model identifier codes for all systems authorized for Mountain Lion. Here's how to locate it:

From original installer: (Control-click, Show package contents)

Contents > Shared Support > InstallESD.dmg

Mount volume, then:

System > Library > CoreServices > PlatformSupport.plist

If you have XCode installed (the developer toolkit, available free from Apple), you can open the .plist and read the relevant model identifier codes listed under SupportedModelProperties. The board IDs in that .plist (under SupportedBoardIds) won't mean anything to most of us; I haven't located a comprehensive reference source yet. But the model identifiers are commonly documented, and can be found in utilities like MacTracker.

The .plist document is a Preferences file, which tells the installer what it can and can't do. The existence of the PlatformSupport.plist and the neighboring InstallableMachines.plist in the CoreServices folder give the Installer a range of acceptable hardware on which they can run. It's checking the motherboard ID, not the CPU only; if your logic board doesn't match any of the board IDs in the .plists, the Installer will cancel the operation.

Mark's first-gen Core Duo iMac is an A1174 20 inch (model identifier iMac4,1). The oldest iMac system generation supported by the Mountain Lion Installer is iMac7,1 - A1224/A1225, the mid-2007 first aluminum generation.

If Mark's feeling experimental, what he might try is to install Mountain Lion on an external drive connected to a supported system, then connect the drive to his white iMac and see if he can boot from it. Very often, the Installer is what's doing the system check, rather than the OS itself.

But generally, I agree with machead3: There comes a point where you have to cut your losses. Even if you can get a later OS onto this box, there's a good reason 10.8 wasn't supposed to be installed. It'd probably be a dog, especially since your system is limited to 2GB RAM.

FYI, the same PlatformSupport.plist and InstallableMachines.plist are in the System>Library>CoreServices folder in the 10.7/Lion Installer, but both .plists list only board ID codes.

Was this answer helpful?

Score 1

Comments:

I most of the Core 2 Duo systems have 32-bit EFI which is why they can't run Mountain Lion, unlike Lion which still had 32-bit services, ML does not.

by

Here's the Writeup from EveryMac for this system" "This system can run the last version of OS X 10.7 "Lion" if upgraded to at least 2 GB of RAM. Although it has a 64-bit processor, it has a 32-bit EFI and is not capable of booting into 64-bit mode. It does not support "OpenCL" either."

by

Add a comment

Add your answer

Mark will be eternally grateful.
View Statistics:

Past 24 Hours: 3

Past 7 Days: 8

Past 30 Days: 42

All Time: 7,938