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#41942 - 09/25/16 07:10 AM Which OS is downloaded in a clean install?
jchuzi Offline


Registered: 08/04/09
Loc: New York State
This is, hopefully, only a theoretical question.. My iMac came with Yosemite and I'm now running El Capitan. If I have to do a clean install via Recovery Partition, which OS is downloaded? Will it be Yosemite, El Capitan, or Sierra? Only Sierra is currently available from Apple via App Store.
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OS 10.15.3, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365

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#41944 - 09/25/16 08:15 AM Re: Which OS is downloaded in a clean install? [Re: jchuzi]
MacManiac Offline
Moderator

Registered: 08/04/09
Loc: Paradise....on the central Ore...
There are several variables in your question that can only be answered by booting from the recovery partition and SEEING which OS is installed therein......whichever OS you find there, THAT OS is the one which governs your clean install from the recovery partition.

I'm leaning toward El Capitan......

Let us know.
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#41947 - 09/25/16 08:47 AM Re: Which OS is downloaded in a clean install? [Re: MacManiac]
jchuzi Offline


Registered: 08/04/09
Loc: New York State
I didn't think that an OS was installed in the recovery partition. AFAIK, the recovery partition downloads the OS from Apple and then installs it. Am I missing something?
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Jon

OS 10.15.3, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365

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#41948 - 09/25/16 08:55 AM Re: Which OS is downloaded in a clean install? [Re: jchuzi]
artie505 Online


Registered: 08/04/09
When you install from your recovery partition you get the latest version of OS X/mac OS that was actually installed on your Mac; Internet recovery gets you the version with which your Mac shipped, so, in your instance, El Cap and Yosemite, respectively.

You're correct about there being no version of OS X installed in a recovery partition, which is, after all, only about 500 MB in size.


Edited by artie505 (09/25/16 09:00 AM)
Edit Reason: More
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#41949 - 09/25/16 09:13 AM Re: Which OS is downloaded in a clean install? [Re: artie505]
jchuzi Offline


Registered: 08/04/09
Loc: New York State
Thanks, Artie, for clearing that up.
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Jon

OS 10.15.3, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365

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#41950 - 09/25/16 09:43 AM Re: Which OS is downloaded in a clean install? [Re: jchuzi]
dkmarsh Offline

Moderator

Registered: 08/04/09

My Mac mini (Late 2012) shipped with Mountain Lion installed. I subsequently upgraded to Mavericks, and then Yosemite.

I took a look within my own Recovery Partition, and found BaseSystem.dmg. Mounting the disk image—OS X Base System—yielded, among other things, Install OS X Yosemite.app. The Base System also includes an Applications folder with Safari and a Utilities folder containing Disk Utility, Firmware Password Utility, Reset Password.app, Startup Disk.app, System Information, and Terminal. So it appears to be very much like the old install CDs as far as the presence of a compact OS is concerned.

I guess it depends what you mean by "has an OS installed." Any disk or disk image that can boot the computer technically qualifies. But the material to be installed—the full-fledged OS—is not on the Recovery Partition.
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#41951 - 09/25/16 10:01 AM Re: Which OS is downloaded in a clean install? [Re: dkmarsh]
MacManiac Offline
Moderator

Registered: 08/04/09
Loc: Paradise....on the central Ore...
...and one additional variable that hasn't been mentioned here is "what originated the recovery partition?"

If the boot drive is a clone produced by a third party cloning utility it might NOT update the recovery partition in the process....leading to the possibility of having an updated OS but NOT having a similarly updated recovery partition.
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#41952 - 09/25/16 12:36 PM Re: Which OS is downloaded in a clean install? [Re: MacManiac]
joemikeb Offline

Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
From personal experience I can certify…
  • not all clone utilities or techniques clone the Recovery Drive. The only one I have personally tested that successfully cloned the Recovery Drive was Carbon Copy Cloner. 👍There may be others but either I have not tested them or they did not when I last tested them.
  • the one time I attempted to install from a Recovery Drive when the Recovery Drive and the installed boot volume did not match, I had to erase the boot volume, use the RD to reinstall the previous OS X version, restore everything else from the Time Machine backup.😠
  • beta installers do NOT update the Recovery Drive (which is good in case you have to revert) 👈
  • upGRADE installers create or upgrade the Recovery Drive
  • upDATE installers seldom, if ever, update the Recovery Drive
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#41954 - 09/25/16 01:35 PM Re: Which OS is downloaded in a clean install? [Re: joemikeb]
jchuzi Offline


Registered: 08/04/09
Loc: New York State
Thanks to all for that information. Apple does not make it possible to download pre-Sierra installers either via their website or App Store. Considering that it is possible to do just that via the recovery partition, if one knew the codes involved (I may be using the wrong term so please correct me), one should be able to get those installers on demand. Probably, this violates some aspect of the EULA but I'm floating this as a possibility.

Comments, anyone?
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OS 10.15.3, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365

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#41956 - 09/25/16 04:59 PM Re: Which OS is downloaded in a clean install? [Re: jchuzi]
dkmarsh Offline

Moderator

Registered: 08/04/09

Quote:
Apple does not make it possible to download pre-Sierra installers either via their website or App Store.

That's not quite right. Any OS X version that you've "purchased" (i.e. downloaded from the App Store) should be re-downloadable by going to the Purchased tab. In your case, you won't see Yosemite there because your Mac shipped with it, but you should see El Capitan.

Just click on the Download button. (Instructions for saving the installer without installing the OS are readily googleable.) If the button is dimmed and reads Downloaded instead, that means you've already got a copy of the installer somewhere.
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#41958 - 09/26/16 12:32 AM Re: Which OS is downloaded in a clean install? [Re: MacManiac]
artie505 Online


Registered: 08/04/09
Originally Posted By: MacManiac
...and one additional variable that hasn't been mentioned here is "what originated the recovery partition?"

If the boot drive is a clone produced by a third party cloning utility it might NOT update the recovery partition in the process....leading to the possibility of having an updated OS but NOT having a similarly updated recovery partition.

And in a similar but different vein...

I've got two El Cap recovery partitions on my deuced Mac(hina), one created when I installed the OS and one created by Carbon Copy Cloner.

If I now upgrade to Sierra, which will do its own partition thing, can I archive the cloned El Cap partition and have dual recovery ability?
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#41970 - 09/26/16 07:19 AM Re: Which OS is downloaded in a clean install? [Re: artie505]
joemikeb Offline

Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
If you mean two partitions (volumes) on the same physical drive there will only be one Recovery Drive and when you install Sierra that will be a Sierra Recovery Drive, so your dual recovery would be severely compromised. If those partitions (volumes) are on separate physical drives, I would verify..
  • if there is a Recovery Drive (RD) on each drive?
  • what is the OS version of the RD on each drive and does it match the OS version installed on that drive?
  • can you actually boot the RD on each drive?
How do you intend to "Archive" the El Capitan partition and would that include the El Capitan RD?

I am putting all this emphasis on the RD because I have found it to be highly valuable in recovering three different Macs whose boot volumes had been damaged in one way or another. Without their RDs these Macs would have been very difficult to restore without losing all their data. (The user's in all three cases either had no backup or their backups were unusable for one reason or another.)

The surest way of doing what you propose would be to have Sierra and El Capitan on separate disk drives and personally I would put the "Archived" El Capitan on its own external drive and disconnect it from the system unless It was in use. I have actually done that using an OWC Envoy Pro mini USB 3 SSD and it worked quite well. I never had a need to recover from it, but I can boot and run from both the RD and the boot volume on the drive. Rotating rust would have been cheaper, but the SSD is noticeably faster and is basically an oversized thumb drive so it is very portable.
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#41979 - 09/26/16 10:06 AM Re: Which OS is downloaded in a clean install? [Re: joemikeb]
dkmarsh Offline

Moderator

Registered: 08/04/09

Quote:
If you mean two partitions (volumes) on the same physical drive there will only be one Recovery Drive...

That's not true.

I have two partitions on my Mac mini's internal drive: one with Mavericks and one with Yosemite. Each partition has its own Recovery drive. If artie installs Sierra on his boot volume but leaves the clone volume untouched, he will have a Sierra Recovery drive on the former and an El Capitan Recovery drive on the latter.
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#41996 - 09/27/16 01:10 AM Re: Which OS is downloaded in a clean install? [Re: dkmarsh]
artie505 Online


Registered: 08/04/09
Responding to both you and joemike...

All points well taken, but neither of you has touched on what I'm really thinking, probably because neither of you has considered the matter with respect to a recovery partition created by CCC.

A CCC recovery partition is a disc image located at /Library/Application Support/com.bombich.ccc/Recovery HD.dmg, and I was wondering if simply having the dmg somewhere on my deuced Mac(hina) without the presence of an appropriate OS would be a qualifying circumstance. (I won't have time to do what I now see is the requisite checking until I get back from FL next week.)
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#42002 - 09/27/16 08:22 AM Re: Which OS is downloaded in a clean install? [Re: artie505]
joemikeb Offline

Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Originally Posted By: artie505
A CCC recovery partition is a disc image located at /Library/Application Support/com.bombich.ccc/Recovery HD.dmg, and I was wondering if simply having the dmg somewhere on my deuced Mac(hina) without the presence of an appropriate [*]boot.efi OS would be a qualifying circumstance. (I won't have time to do what I now see is the requisite checking until I get back from FL next week.)

Good question‼️

In the Recovery HD.dmg I found...
  1. BaseSystem.Chunklist
  2. BaseSystem.dmg
  3. boot.efi
  4. com.apple.Boot.plist
    1. Kernel Cache — \com.apple.boot\prelinkedkernel
    2. Kernal Flags — rp=file:///com.apple.recoveryboot/BaseSystem.dmg
  5. PlatformSupport.plist
    1. SupportedBoardids — a list of 62 logic board numbers
    2. SupportedModeProperties — alist of 54 Mac model ids (Macmini6.2)
  6. prelinkedkernel
  7. SystemVersion.plist
    1. ProductBuildVersion
    2. ProductCopyright
    3. ProductUserVisibleVerion — 10.12
    4. ProductVersion — 10.12

If there is anything that makes the Recovery HD unique to a particular OS version it is ProductVersion number, or deeply embedded in the BaseSystem.dmg, and/or is part of the negotiation between the BaseSystem and the Apple servers when the actual system installer is selected for download.

Artie will be returning from Florida next week while my wife and I will be on an adults only (no children or grandchildren) visit with our good friends Mickey and Minnie near Orlando.


Edited by joemikeb (09/27/16 08:26 AM)
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#42090 - 10/07/16 10:21 PM Re: Which OS is downloaded in a clean install? [Re: joemikeb]
artie505 Online


Registered: 08/04/09
Originally Posted By: joemikeb
Originally Posted By: artie505
A CCC recovery partition is a disc image located at /Library/Application Support/com.bombich.ccc/Recovery HD.dmg, and I was wondering if simply having the dmg somewhere on my deuced Mac(hina) without the presence of an appropriate [*]boot.efi OS would be a qualifying circumstance. (I won't have time to do what I now see is the requisite checking until I get back from FL next week.)

Good question‼️

But based on a bad assumption!

Originally Posted By: CCC
CCC creates an archive of the Recovery HD by default, and this archive can be used to create a Recovery HD partition in the future as necessary.

As per the above quote, /Library/Application Support/com.bombich.ccc/Recovery HD.dmg is not a recovery partition.

The actual CCC recovery partition is a separate (roughly 1GB) volume carved out of the volume on which the clone that it lives with resides; it can be seen and accessed from an option boot as opposed to the command-R boot necessary to access Apple's recovery partition.

Edit: Hmmm... Archiving the recovery partition is a neat idea...enables the creation of a new one on a replacement drive.


Edited by artie505 (10/08/16 01:07 PM)
Edit Reason: More
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Moderator:  alternaut, dkmarsh, joemikeb