Trying to downgrade Mountain Lion to Lion

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Level 1

5 points

Trying to downgrade Mountain Lion to Lion

hey team:

I've been attempting to downgrade Mountain Lion 10.8.5 to Lion for a client's Mac Pro machine and am having a hard time doing something that I've done easily in the past.

The Mac Pro came with Lion installed, but for some reason I advised my client to upgrade to Mountain Lion, thinking that Apple would improve their operating system. Since installing Mountain Lion, he's had trouble with large file transfers crashing, screen turning green / grey and then crashing, FCP 7 frame issues on playback, etc etc

I've since made a Lion install clone to USB, and my Macbook Pro laptop will boot to that when I hold the Option key.

Holding the option key on the keyboard on the Mac Pro at startup however, with the same Lion USB inserted, yields the startup tone and a black screen. No option to boot to an alternate drive. No Apple logo. Nothing.

I've also made a Mountain Lion USB install, and holding option with that inserted, yields the startup tone and a black screen. No option to boot to an alternate drive. No Apple logo. Nothing.

When I hold Command-Option-R, it will boot from the Mountain Lion USB, but not the Lion USB, even though the same workflow works fine on the laptop.

I've even tried booting to my Snow Leopard DVD; the DVD drive spins up for a while, then stops. All with a black screen. I understand though that this might be a newer machine that won't support Snow Leopard (which is ridiculous by the way -- how is this good enough Apple?)

Is there something about 10.8.5 that locks you into 10.8.5 on a MacPro tower? This machine came with Lion installed, so obviously it can run it. Why does holding Option on bootup on the MacPro no longer work? The Option-boot works on my Macbook Pro laptop, which is also running 10.8.5.

Thanks for any help and advice!

Paul

Posted on Sep 28, 2013 11:01 PM

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Answer 1

kaz-k

Level 8

49,188 points

Sep 29, 2013 12:24 AM in response to PW1000

Resetting NVRAM could solve your problem.

http://support.apple.com/kb/HT1379?viewlocale=en_US

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Answer 2

PW1000 Author

Level 1

5 points

Sep 29, 2013 1:20 PM in response to kaz-k

Hmmm still doesn't Option-boot. I think I'll downgrade one of my laptops and then use Carbon Copy Cloner to install onto the MacPro. Wow workflow!

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Answer 3

The hatter

Level 9

60,990 points

Sep 29, 2013 2:36 PM in response to PW1000

You cannot use a retail 10.6.3 only OEM 10.6.4 Mac Pro shipped with and uses you can special order. I suspect your Lion install as happens is "not right."

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Answer 4

PW1000 Author

Level 1

5 points

Sep 30, 2013 2:21 PM in response to PW1000

Solved my problem cloning an old Snow Leopard machine with Carbon Copy Cloner -- a great free program that saved me this time -- to an external hard drive.

Mac Pro still wouldn't Option mount the cloned drive (I'm wondering if it's a hardware problem on this tower), so I set the tower to Target Mode, attached a Firewire to my laptop, and attached the external hard disk with the cloned Snow Leopard machine also to my laptop.

After the Mac Pro tower drive appeared on my lappy as a firewire drive, I wiped it using my laptop's Disk Utility, then cloned the cloned Snow Leopard external hard drive to the Mac Pro tower hard drive.

Mac Pro started up fine -- and apparently this tower can run Snow Leopard! But I then immediately updated to Lion using the USB stick previously mentioned, which was succesful first time out. Running Software Update brought me up to the latest version of Lion 10.7.5

Thank goodness for Carbon Copy Cloner -- and that I had a laptop still running Snow Leopard in my arsenal!

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