Can I install an OLDER OS on my iMac?

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Level 1

20 points

Can I install an OLDER OS on my iMac?

I inherited my late father's iMac so now I have TWO of them. I need to run one on OS 10.6 and the other on the latest OS. Since my Finale music app and Adobe Acrobat 7.0 will not run on the new OS, I want to change the OS on the inherited iMac back from Yosemite to 10.6 so that when I need to use Adobe, I can just fire it up. I intend to upgrade my iMac, which is bigger, to the latest OS then and will just run Finale and Adobe on the older iMac. I realize that this is confusing and hope that someone can understand and advise me how to backward install an OS. Thank you.

iMac, Mac OS X (10.6.8)

Posted on Jan 13, 2015 2:34 PM

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Answer 1

KiltedTim

Level 10

195,195 points

Jan 13, 2015 2:36 PM in response to Sliphorn

If the machine supports it, sure. Since we don't have details on what model iMac it is, we can't say for sure.

Boot with the OS X 10.6 installation DVD, wipe the drive and install it.

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Answer 2

Sliphorn Author

Level 1

20 points

Jan 13, 2015 3:55 PM in response to KiltedTim

It would not let me change to the older startup item. It kept showing a yellow warning sign over the startup disc icon and saying it could not be done with this OS. I assume the second part of your directions mean to do something to get rid of the OS 10.9.4 somehow ("wipe the drive"). What do I do to achieve this? I had started with the OS 10.6 DVD and holding down the C key.

It is a 20 inch iMac from early 2009.

Thanks.

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Answer 3

Jan 13, 2015 6:11 PM in response to Sliphorn

The OS X installer will not allow you to install an older version of OS X over a newer version. The first thing you must do is erase the disk drive so that the installer no longer sees the newer version of OS X.

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Answer 4

Eric Root

Level 10

684,027 points

Jan 13, 2015 6:30 PM in response to Sliphorn

As KilltedTim posted, you need to provide details about the computer you are trying to install Snow Leopard on.

Install OSX Restrictions

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Answer 5

kahjot

Level 4

2,462 points

Jan 13, 2015 9:14 PM in response to Sliphorn

If it's a 2009 Mac, it should be able to boot a Snow Leopard disk. Did you use a retail DVD, or a system disk that came with the iMac?

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Answer 6

Sliphorn Author

Level 1

20 points

Jan 14, 2015 5:45 AM in response to Eric Root

What details are needed? It is a 2009 iMac? I am unclear about this. Thanks.

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Answer 7

Sliphorn Author

Level 1

20 points

Jan 14, 2015 5:47 AM in response to kahjot

I have the install DVD that I bought from Apple and inserted it. The disc started to install and when I got to the "where do you want to do this" part, the next dialog box said the iMac could not be booted up from this older OS. It shows up in the boot up window right next to the OS 10.9.4 one.

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Answer 8

Sliphorn Author

Level 1

20 points

Jan 14, 2015 5:48 AM in response to Allan Eckert

I am not very savvy on how to erase a disc drive and what precautions are needed before doing so. I assume (?) that I need to put all docs on a thumb drive and re copy once the old OS is working. Can you please detail steps to take? Thank you.

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Answer 9

kahjot

Level 4

2,462 points

Jan 14, 2015 6:01 AM in response to Sliphorn

Please let us know exactly what Mac you have, and exactly what DVD you are trying to use. Click on About this Mac in the Apple Menu, Click on More Info in the box that appears, then look at the Model Identifier, and tell us what it says.

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Answer 10

Eric Root

Level 10

684,027 points

Jan 14, 2015 6:35 AM in response to Sliphorn

If it is a 2009 iMac, you should be able be able to install 10.6 on the computer. The first thing you need to do is backup the data you want to save using Time Machine, by copying the files to a thumb drive as you posted, or by creating a clone. Once you have done that, insert the Snow Leopard DVD and boot the computer from the DVD. Then go to the Utilities menu and select Disk Utility. Select the hard drive at the top, go to the erase tab, select Mac OS Extended (Journaled), and then erase.

Once the disk is erased, then you should be able to install 10.6. After the installation is complete, reboot normally and use the link below to update to 10.6.8

10.6.8 Combo Updater

Copy your data back to the computer. Then run Software Update until there are no more updates.

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Answer 11

Sliphorn Author

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Jan 14, 2015 4:20 PM in response to Eric Root

Eric:

I have done the backup and booted up from the 10.6.3 DVD but do not see the OS's in the left window above where you have "Snow Leopard" selected. Instead I have two drive icons with one being the Macintosh HD and the other being Hitachi. The other two are the 10.6 install disc and a disc icon with HL- DT - HT and more info. There is no Yosemite icon to erase. For some reason I cannot make a screen shot of it to show you. Please remember that your dialog box above is probably in OS 10.6 and mine will come up with the OS 10.9.4 set up since that is what is still in use. Maybe we are getting closer but I do not know. Thanks.

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Answer 12

Sliphorn Author

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Jan 14, 2015 4:44 PM in response to kahjot

Here are a couple screen shots I WAS able to get off the iMac in question. Hopefully this will answer the question about what I have. Thanks.

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Answer 13

Eric Root

Level 10

684,027 points

Jan 14, 2015 4:45 PM in response to Sliphorn

You want Macintosh HD. I renamed mine so I knew which partition held which OS. The screen shot I posted hasn't changed since I took the screen shot in 10.8, so the information is the same.

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Answer 14

Sliphorn Author

Level 1

20 points

Jan 15, 2015 10:35 AM in response to Eric Root

Thanks. I am busy today and will try late tonight or more likely tomorrow to do this. Is there a way to make screen shots in OS 10.9.4? I tried the usual short cut but it did not work. I guess I DID make a screen shot as shown in my last post but could not get it to make one at the point of showing the dialog box for erasing.

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Answer 15

Eric Root

Level 10

684,027 points

Jan 15, 2015 4:51 PM in response to Sliphorn

You are welcome. Screen shots haven't changed since at least 10.6.

Screen shots

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