# iMac won't boot after memory upgrade



## pollock (May 29, 2010)

Hello,

Recently I have upgraded my iMac with 2GB additional memory and since then my iMac won't to boot properly.
I am running the leopard latest version and I have 3 gb memory currently installed.

I have attached message appeared on the screen while system is starting.


> Panic(cpu 0 caller 0x0043913F): Unable to find driver for this platform : \ACPI\.\n@/Source Cache/xnu/xnu-1228.15.4/iokit/Kernel/IOPlatformExpert.cpp:1407
> 
> Debugger called: <panic>
> 
> ...



Many thanks

Pollock


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## LMeinhardt (May 29, 2010)

Whats the memory brand? Did you change both memory slots? Are the new memory compatible with the previous ones? Removing the new memories, does it resolve the problem?


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## pollock (May 29, 2010)

I installed new Kingston 2gb memory module (kta-mb800/2g).
My old memory is Samsung M470t2864qh3

I booted successfully yesterday but today won't start up...


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## djackmac (May 29, 2010)

Which iMac is this? I'd go and try to reseat the RAM. If it is one of the older Intel iMacs with the white levers for popping the RAM out, those levers pop out the RAM for both chips. So its possible you thought the one chip stayed seated when you added the other one. So go ahead and try reseating until it works. If you still can't get it to work, run both chips alone and verify which ones bad. Test both slots also to make sure you didn't blow a slot when you did the RAM.


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## pollock (May 29, 2010)

thanks,

I have already swapped memory in the slot and seems to work fine now.


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