usb boot installer not recognized by 2012 Mac mini but recognized by 2010 MacBook Pro

Question

usb boot installer not recognized by 2012 Mac mini but recognized by 2010 MacBook Pro

I have a mid-2010 MacBook Pro and a 2012 Mac Mini, both running Mountain Lion 10.8.5. Decided it was perhaps time to update them to El Capitan.

Downloaded the El Capitan installer from the App Store. Exited the installer when it started.

Used the one-liner "createinstallmedia" command recommended by Apple and various other websites, I created a usb bootable installer.

Decided to update Mac Mini first. But System Preferences/StartUp Disk shows only the OS X and my Boot Camp partitions to choose. Does not list

the USB install (though the USB installer flash drive mounts no problem).

When I shut down the Mac Mini and plug in the flash drive with installer, hold down Option key and boot to the Boot Manager, I see the OS X partition,

the OS X 10.8.5 Recovery partition and the BootCamp partition (has Windoze 7 on it) but no USB bootable.

Tried the usb bootable installer in each of the 4 USB ports one after the other. It is not recognized in any of them.

Began to think the usb bootable installer flash drive was in fact not recognized as bootable.

So I stuck the flash drive in the 2010 MacBook Pro and powered up and held down Option key. At the boot manager, I see the OS X partition

and the OS X 10.8.5 Recovery partition BUT I also see the USB bootable installer flash drive as a bootable entity.

My question is: why does the Mac Mini not see this flash drive as a bootable entity whereas the MacBook Pro does?

There is one significant difference I can think of that might be affecting this. The Mac Mini has a Boot Camp partition on it containing Windows 7.

Does the Boot Camp partition prevent the USB bootable flash drive from being recognized as a bootable source?

Is there a limit, for example, on the number of bootable partitions the Boot Manager will display or recognize?

Thanks for anyone's help or direction on this.

Keith

Mac mini (Late 2012), OS X Mountain Lion (10.8.5)

Posted on Jun 27, 2016 12:28 PM

Reply

Answer 1

theratter

Level 4

3,961 points

Jun 27, 2016 1:13 PM in response to keithfrometobicoke

Here is how the flash drive installer is made. I don't believe you did the right procedure.

Make your own El Capitan flash drive installer

You need a freshly partitioned and formatted USB flash drive with at least 8GBs. The name of the flash drive should be the system default name, "Untitled." Open the Terminal in the Utilities folder. Copy and paste the following command line in its entirety into the Terminal window.

sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath "/Applications/Install OS X El Capitan.app"

Press RETURN, enter your admin password then press RETURN again. Your entry will not echo to the Terminal window.

The installer must be in your Applications folder where it was originally downloaded or change the paths in the above command line. Wait for the process to complete which will take quite some time.

Reply

Answer 2

Jun 27, 2016 7:07 PM in response to theratter

I'm afraid I did. The flash drive is a Kingston 32 GB usb3-capable one. I partitioned and formatted it (GUID partition table/OSX extended,journaled) before using it with the createinstallmedia command. I renamed the drive from Untitled to OSX_install or something like that and adjusted the createinstallmedia command to have the matching name for the drive. The command I pasted into the Terminal was one identical to the one you indicate (with the flash drive name or label changed appropriately).

The installer, of course, was in my Applications directory (folder). It took a bit of time but not enormous (usb3).

What is different here is not the drive. My Macbook Pro recognizes this drive as being bootable. The Mac mini does not. I think this means there is something

different between the two systems since the flash drive is the same. This could be drivers but the mountain lion boot manager should in both cases have the drivers it needs for either system.

My money is on the subtleties of the boot manager in a dual boot environment. The major difference between the two systems is that the Mac mini has a boot camp partition. That means it has 3 partitions before the usb flash drive is considered. the MacBook Pro has only two partitions before the flash drive is considered.

There may be something about the boot manager in a multi-partition dual boot scenario that makes it unable to see the flash drive as a boot source.

What we need is someone who knows the intricacies of that part of the OS X -associated software.

Keith

Reply

Answer 3

theratter

Level 4

3,961 points

Jun 27, 2016 10:50 PM in response to keithfrometobicoke

There is nothing that would be different about the Mini vs. the MBP as far as using the USB installer since the installer is "universal." The problem, if there is one, may be an inability of the Mini to use a Kingston flash drive. If you use Option booting, then the installer should be displayed so you can choose it as the boot device. I'd try a different flash drive from a different manufacturer. You might try using a PNY or Lexar device. I've never had issues with them, but I definitely have had Macs that would not boot from a Kingston flash drive.

Reply

Answer 4

Jun 28, 2016 11:38 AM in response to theratter

I have heard this suggestion several times already. While it suggests the kind of voodoo that Windows sysadmins sometimes engage in, I will give this a try. It makes no sense to me unless usb2 and usb3 are not industry standards that different manufacturers adhere to. It also does not explain why the drive is recognized as a boot source by the MacBook Pro but not the Mac Mini even though the MacBook Pro is much older. I'd still like to hear from an Apple engineer who understands the GPT/MBR partitioning fakery that goes on to make it possible to dual boot using Bootcamp. I did actually find something on this that appeared to be suggesting that the boot manager in this case cannot show more than 3 partitions but the article was somewhat confusing since master boot record and GUID partitioning and the use of EFI 1.1 instead of EFI 2.1 are areas that I do not have any good understanding of.

I'll try another flash drive and see if it makes a difference.

I agree that the installer ought to be universal. But the hardware and firmware in different Mac products is different so it is not necessarily a surprise the the boot process is not the same. And as I mention, there is an additional partition on the Mac Mini that is not on the MacBook Pro.

Keith

Reply

Answer 5

leroydouglas

Level 10

199,344 points

Jun 28, 2016 11:45 AM in response to keithfrometobicoke

keithfrometobicoke wrote:

I'd still like to hear from an Apple engineer who understands the GPT/MBR partitioning fakery that goes on to make it possible to dual boot using Bootcamp.

If you wan to start a conversation with Apple engineers you will have to file a bug report.

With your same Apple ID you can sign up for a free Developers Account

Bug Reporter https://bugreport.apple.com/

Reply

Answer 6

keg55

Level 6

11,755 points

Jun 28, 2016 11:48 AM in response to keithfrometobicoke

How about simply copying the Install OS X El Capitan.app file into the /Applications folder on your Mac Mini and running it from there?

I believe you can update OS X when there is a Bootcamp partition because you're only affecting the OS X partition and not the boot loader or startup manager. I don't remember as it's been awhile since I've done that. So, maybe having Bootcamp on is causing the issue of trying to boot from the thumb drive.

Reply

Answer 7

Jul 8, 2016 10:50 AM in response to keg55

Sorry to be so long about replying but I was out of town last weekend and just haven't had time to update this.

Ok, so I followed theratter's advice, went to a Best Buy and bought a cheapie Lexar ( i say cheapie because they now make their usb connectors partly out of breakable plastic which in my opinion is not a good thing) flash drive. It was a 16 GB usb3-capable flash drive. Note my "science experiment" :-) did not ensure there was only one variable. Both the manufacturer and the size of the flash drive were different. I put a copy of the El Capitan boot installer on this 16 GB Lexar flash drive and, lo and behold, it is recognized as bootable by both the Mac Mini and the MacBook Pro. This was either because the flash drive manufacturer was different or the flash drive size was different. In fact, just over a week ago, I updated my Mac Mini from the boot installer on this Lexar flash drive to El Capitan. So, thanks to theratter for his or her arcane suggestion to try a Lexar or PNY flash drive instead of Kingston. The Mac Mini (2012) recognized the El Capitan boot installer only on the Lexar 16 GB usb3 flash drive. The MacBook Pro (mid 2010) recognized the boot installer on both the Lexar 16 GB and the Kingston 32 GB flash drives.

Thanks to theratter for the suggestion.

In reply to keg55, yes, you can run the boot installer from the /Applications directory but,as you probably realize, the install process erases this file once the upgrade has completed and you then need to download another 6 GB from Apple to upgrade any other Apple PC you have. If your hard drive decides to join the choir celestial, you need a boot source

to install OS X and later restore your backed up files and if you don't have a boot installer on a local drive, you've got to download it from Apple.

Bootcamp was not a problem. When I booted off the Lexar flash drive, 4 bootable partitions showed up in the boot manager's screen (OS X, OS X Recovery, Boot Camp, and the Lexar flash drive). The upgrade to El Capitan from the Lexar flash drive did not touch my Boot Camp partition which had a copy of Windows 7 on it. I could still boot into WIndows 7 on that partition after the upgrade.

Cheers all.

Reply