Migrate/downgrade 10.8 iMac

Danny84

macrumors newbie
Original poster
Jan 9, 2010
8
0
I have two macs: an old (2009 I think) iMac running Snow Leopard/10.6.8, and a new (late 2011) iMac running Mountain Lion. I want to keep my old system as is, but move it to the new computer for faster speeds. In other words, I want to downgrade the 10.8 computer to 10.6.8 and clone my old iMac onto the new one.

I was able to erase the new mac's hard drive, but I can't seem to downgrade it since it won't boot off the Snow Leopard disk (I get a kernel panic). Any help would be greatly appreciated.

(edit) Just to clarify, I do not want to upgrade my old iMac to Mountain Lion — I find Snow Leopard to be by far the better operating system. But that discussion's for another day.
 

Puevlo

macrumors 6502a
Oct 21, 2011
633
1
Are you using the Snow Leopard disk that came with the 2009 iMac? If so, it is specific to that model of iMac and won't work on your new one. Even a Snow Leopard retail disk likely won't work as it'll have been made before the 2011 iMac.

You'll probably have to install Snow Leopard clean onto an external hard drive from the 2009 iMac and clone it onto the new one.
 

G-Mo

macrumors 6502
Nov 6, 2010
466
2
Auckland, NZ
Make sure the 2009 iMac is running 10.6.8. Put the 2011 iMac in Target Disk Mode and connect to 2009 iMac. Use Disk Utility to erase the 2011 hard drive. Use Carbon Copy Cloner to clone drive from 2009 iMac to 2011. Voila!

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I am pretty positive Snow Leopard won't run on newer Macs.
The mid 2011 iMacs will run Snow Leopard just fine.
 

justperry

macrumors G4
Aug 10, 2007
10,494
5,922
I'm a rolling stone.
Make sure the 2009 iMac is running 10.6.8. Put the 2011 iMac in Target Disk Mode and connect to 2009 iMac. Use Disk Utility to erase the 2011 hard drive. Use Carbon Copy Cloner to clone drive from 2009 iMac to 2011. Voila!

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The mid 2011 iMacs will run Snow Leopard just fine.
Yeah, I read half of that thread and it seems to work, thought it wasn't supported.
 

mcpix

macrumors 6502
May 13, 2005
289
69
I purchased a Snow Leopard disk from Apple that had 10.6.8 on it for just that purpose (not the regular retail disk). I purchased it through the help line. The first person told me it was not possible, but her supervisor found the disk for me.

I still have Lion on that iMac, but I wanted the disk just in case I decided to downgrade.
 

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