Factory installed 10.11 downgrade

surfit

macrumors newbie
Original poster
Nov 3, 2015
4
0
We got several new iMacs this past Friday (10/31) which all came with not what was ordered, instead with 10.11. Have done everything including destroying the Fusion drive and recreating it so that no possibility of 10.11 exists on either the SSD and HD. Still the machine will not except Yosemite or any other OS older than 10.11. Even after CCCing 10.10 to the rebuilt Fusion, still will not accept the OS. Called Apple and they said once its been factory installed you cannot go back.

Must be a way around this.....................

Any input would be appreciated.
 

Ebenezum

macrumors 6502a
Mar 31, 2015
782
259
If you are desperate you might be able to use Pike´s Macosxbootloader to install 10.10.

I tried to downgrade Mac Mini 2014 from 10.10 to 10.9 some months ago without success, either I misunderstood instructions or it didn't work for technical reasons.

Maybe you have better luck than I did.
 

chrfr

macrumors G3
Jul 11, 2009
9,233
3,198
We got several new iMacs this past Friday (10/31) which all came with not what was ordered, instead with 10.11.
If they are 2015 iMacs, you'll need to use 10.11; there's no way they can run 10.10.x.
 
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Morpheo

macrumors 65816
Feb 26, 2014
1,273
1,588
Paris/Montreal
If you are desperate you might be able to use Pike´s Macosxbootloader to install 10.10.

I tried to downgrade Mac Mini 2014 from 10.10 to 10.9 some months ago without success, either I misunderstood instructions or it didn't work for technical reasons.

Maybe you have better luck than I did.
As mentioned on Pike's page his bootloader is for unsupported models of MacPros and Macbook Pros. OP has iMacs...
 

surfit

macrumors newbie
Original poster
Nov 3, 2015
4
0
May I ask why you'd want to install 10.10 on these?
In an enterprise environment we don't want to introduce an OS that is so new. There are still many unknowns about 10.11 and many issues are still showing up. We don't want 10.11 and its issues until they have been resolved. Yosemite works fine with AD and all our other Macs are running on 10.10.
 

chrfr

macrumors G3
Jul 11, 2009
9,233
3,198
In an enterprise environment we don't want to introduce an OS that is so new. There are still many unknowns about 10.11 and many issues are still showing up. We don't want 10.11 and its issues until they have been resolved. Yosemite works fine with AD and all our other Macs are running on 10.10.
It's time for your organization to rethink how it handles hardware purchases and OS deployment. You won't be using these iMacs with 10.10.x.
Apple has made El Capitan available for testing for several months; either your organization needs to be sure that 10.11 works and test while it's still in beta, or the company needs to make sure it buys enough old hardware that can still run the now discontinued operating system to cover future needs.
 
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9fiftyfive

macrumors member
Oct 26, 2015
91
15
In an enterprise environment we don't want to introduce an OS that is so new. There are still many unknowns about 10.11 and many issues are still showing up. We don't want 10.11 and its issues until they have been resolved. Yosemite works fine with AD and all our other Macs are running on 10.10.
Put it in to internet recovery mode, and from there you can delete your entire disk's partition. After that, open up "Install OS X", which will prompt you with an installer. The installer will then download the original OS those iMacs came with. You can then re-download Yosemite via the Mac App Store and install it on each computer. Good Luck!
 

Erdbeertorte

Suspended
May 20, 2015
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If these are the new 27" 5k iMacs with Skylake chipset, I can assure you that you can't even boot the normal build of El Capitan 10.11.0. You have to use the preinstalled version or update to 10.11.1, what you also get by internet recovery now.

I don't know if the Late 2015 4k iMacs can run Yosemite, but they also got a different build of El Capitan.
 
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chrfr

macrumors G3
Jul 11, 2009
9,233
3,198
My understanding is that Apple locks all new Macs to the currently shipping OS.
Apple doesn't provide support in older operating systems for newer hardware, but they don't lock any Mac to a given OS. The rule of thumb is that a given computer cannot install or run a version of the OS earlier than what was was installed when it was new. There are exceptions, in cases where a computer's lifespan crosses over several versions of OS X, but for a newly released computer like a 2015 iMac, 10.10.5 won't work.
 

surfit

macrumors newbie
Original poster
Nov 3, 2015
4
0
It's time for your organization to rethink how it handles hardware purchases and OS deployment. You won't be using these iMacs with 10.10.x.
Apple has made El Capitan available for testing for several months; either your organization needs to be sure that 10.11 works and test while it's still in beta, or the company needs to make sure it buys enough old hardware that can still run the now discontinued operating system to cover future needs.
As I stated in my original post we did not order these with 10.11. At this point I'll go back to our purchase agent and see we get these swapped out. The rest of this thread pretty much summed up what I expected.
 

hallux

macrumors 68030
Apr 25, 2012
2,891
563
It's time for your organization to rethink how it handles hardware purchases and OS deployment. You won't be using these iMacs with 10.10.x.
Apple has made El Capitan available for testing for several months; either your organization needs to be sure that 10.11 works and test while it's still in beta, or the company needs to make sure it buys enough old hardware that can still run the now discontinued operating system to cover future needs.
It's not quite that simple. I work in an enterprise environment also, we also support Macs. The business has blocked installation of 10.11 until all security tools (Mcafee and Digital Guardian to name 2) have been updated by the vendor and then gone through a period of testing for compatibility in the environment. The 2 vendors I mentioned previously had committed to 90 days as their window to provide updated apps, the business committed to a period of 90 days after that for delivering the tools for upgrading the Macs in the environment. In our case, I don't think we support any Macs that wouldn't be supported by Yosemite.

As I stated in my original post we did not order these with 10.11. At this point I'll go back to our purchase agent and see we get these swapped out. The rest of this thread pretty much summed up what I expected.
You don't get a choice what OS comes on Macs when you order from Apple (or an authorized Apple reseller). As was noted before, if you got the 2015 iMac there is simply no support for the hardware in versions prior to what shipped on it. Consider it similar to trying to install Windows 9x on a modern computer, the drivers just aren't there. Ok, that may be extreme compared to Apple not supporting new hardware on an OS that's only a year old but you get the picture.
 

chrfr

macrumors G3
Jul 11, 2009
9,233
3,198
It's not quite that simple. I work in an enterprise environment also, we also support Macs. The business has blocked installation of 10.11... In our case, I don't think we support any Macs that wouldn't be supported by Yosemite.
I too work in an enterprise environment supporting Macs and it really is that simple. Either you plan your hardware purchases based on your OS compatibility and buy extras of older, compatible models while they're still being sold, and well before they might possibly be discontinued or updated, or you get the new OS to work. Apple doesn't provide any other options; the model of calling up the Dell rep and ordering new workstations with a 1-or-2-versions-old OS doesn't apply here.
 
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surfit

macrumors newbie
Original poster
Nov 3, 2015
4
0
I too work in an enterprise environment supporting Macs and it really is that simple. Either you plan your hardware purchases based on your OS compatibility and buy extras of older, compatible models while they're still being sold, and well before they might possibly be discontinued or updated, or you get the new OS to work. Apple doesn't provide any other options; the model of calling up the Dell rep and ordering new workstations with a 1-or-2-versions-old OS doesn't apply here.
Well, I'll let you two hash out your differences. I had asked for some simple input, not scripture..... out!
 

Erdbeertorte

Suspended
May 20, 2015
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500
You have to buy the Late 2014 iMac or older to use Yosemite. There is no other option. Apple directly doesn't sell them anymore, just some refurbished. But it depends on the country you are living. In my country there isn't a single 27-inch, but in the US online store there are a few:

http://www.apple.com/shop/browse/home/specialdeals/mac/imac

Maybe some authorized Apple resellers have more of them in stock, in new condition. I saw many of them in the first week of release.
 

davidnayzar

macrumors newbie
Jan 7, 2011
24
5
SF,California
You have to buy the Late 2014 iMac or older to use Yosemite. There is no other option. Apple directly doesn't sell them anymore, just some refurbished. But it depends on the country you are living. In my country there isn't a single 27-inch, but in the US online store there are a few:

http://www.apple.com/shop/browse/home/specialdeals/mac/imac

Maybe some authorized Apple resellers have more of them in stock, in new condition. I saw many of them in the first week of release.
What about dump the EFI boot ROM and modify it? That is the only thing Apple uses to verify the system. It is not rocket science.
 

chrfr

macrumors G3
Jul 11, 2009
9,233
3,198
What about dump the EFI boot ROM and modify it? That is the only thing Apple uses to verify the system. It is not rocket science.
The reasons that older operating systems won't run on newer computers isn't a block in the ROM, but instead it's most often that there are no drivers for the newer hardware in the older operating system. The block is in the installer and that's not especially complex to modify, but it still won't run the computer.
 
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