No Boot Camp on Mojave??? ***?

tineketover wrote:

Is there a chance that Apple will fix this issue eventually as it did when the 3 TB drive was first introduced on the late 2012 iMac, or are there incompatibilities that cannot be fixed?

The 2012 Macs are preUEFI. The first UEFI Macs are late 2013. preUEFI Macs use a Hybrid MBR to mimic a BIOS disk layout, which has two limitations

• 32-bit numbers for partition sizes, which limits the size to 2TB
• Four (4) entries in an MBR

On a 3TB disk, you can have two layouts

• Sandwich - macOS(Part1)+Windows(<1TB)+macOS(Part2) - This uses CoreStorage. Not supported on APFS, because there is no equivalent partitioning methodology. APFS does not support more than 2 disk partitions.
• Non-Sandwich - macOS (<2TB)+Windows>1TB+). This can be supported on APFS and is used on non-3TB disks and 3TB Fusion disks. Apple chose not to pursue this path, but a user is free to choose this method, but BC Assistant is not designed to support this, which implies manual partitioning.

tineketover wrote:

It is certainly bad, as I thought I had a future proof system, especially with the 3 TB replacement drive a few years ago.

See dialabrain's 'Future-Proof' comment. Apple would be out of business if they did not sell new 'features' to you.

tineketover wrote:

It would be good to explain what APFS conversion entails (what does it mean) as this apparently interferes with bootcamp and time machine.

It depends on what you call 'interfers'. 😉

Prepare for APFS in macOS High Sierra - Apple Support

See if your Mac shares space across APFS volumes in System Information - Apple Support

About Time Machine local snapshots - Apple Support

About Apple File System | Apple Developer Documentation

https://developer.apple.com/support/apple-file-system/Apple-File-System-Referenc e.pdf

If you need more reading material, please ask.

The difference is that only on 3 TB Fusion Drives the BOOTCAMP partition is placed between to physical HFS+ partition, which represents one partition on the virtual drive:

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *121.3 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_CoreStorage Macintosh HD 121.0 GB disk0s2

3: Apple_Boot Boot OS X 134.2 MB disk0s3

/dev/disk1 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *3.0 TB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_CoreStorage Macintosh HD 645.2 GB disk1s2

3: Apple_Boot Recovery HD 650.1 MB disk1s3

4: Microsoft Basic Data BOOTCAMP 1.6 TB disk1s4

5: Apple_CoreStorage Macintosh HD 801.4 GB disk1s5

6: Apple_Boot Boot OS X 134.2 MB disk1s6

/dev/disk2 (internal, virtual):

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Macintosh HD +1.6 TB disk2

Logical Volume on disk0s2, disk1s2, ...

XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX <-- hidden due to DSGVO

Unencrypted Fusion Drive

On 2 TB Fusion Drives Bootcamp created only one physical HFS+ partition for the Mac part of the drive. Splitted Mac partitions could be a problem when the Mojave installer tries to convert them to APFS.

But Apple really should overcome this and fix that bug. Disappointing customers, which bought the most expensive iMacs available, is a bad idea. Usually this buyers are opinion leaders, influencing purchase decisions of a lot of people.

The reason actually has to do with Windows and the NTFS format it uses. For a boot partition, an NTFS volume must begin and end within the first 2TB of a physical drive. For Macs with 3TB drives (Fusion or not) there’s a lot of partitioning voodoo that has to take place in order for Boot Camp to work as expected. The partition map on the drive actually breaks the macOS volume up into two pieces and shoves the NTFS partition in the middle, This is all accomplished via Apple’s CoreStorage framework. The end result is that the fragments of the macOS volume are logically stitched back together so that you only see one contiguous macOS volume on your desktop, alongside the Boot Camp volume.

Interestingly, this isn’t the first time this exact situation has occurred. When the 2012 iMac with any flavor of 3TB drive was first released, OS X 10.8 Mountain Lion also was unable to set up a Boot Camp partition on those machines. I still own one of those machines (3TB Fusion) and I had to wait for at least one—though I think it was two or possibly three—point update before Boot Camp was supported on a 3TB drive.

I’m in the same boat, but given the above past occurrence, I’m being patient to see if Apple is able to support these configurations with a point update to Mojave.

Hey, sorry for a late response to you’re issue. It seems like macOS Mojave doesn’t support Boot Camp for you’re Late 2012 iMac. That sucks I know but, there is a way to install Microsoft Windows®️ on you’re Macintosh.

Step 1: Retrieve a disk Copy of Windows

Step 2: Open Disk Utility on Mojave

Step 3: Click Macintosh HD or whatever name you have for you’re Macintosh’s hard drive and click partition.

Step 4: Partition how much space you would want on the volume you are partitioning and when you’re done getting you’re space setup before clicking Apply, click name and name it Windows and then click format and format it as exFAT then click Apply.

Now insert you’re DVD copy of Windows ®️ And wait for you’re iMac to detect it. After that, click restart and as you’re iMac is restarting hold down the option key on the keyboard. When a boot menu of 3 comes up you may see EFI Boot, you’re Mac hard disk and The Windows DVD, click the DVD and when you’re going through the setup and get to the select disk section, click the disk that says Windows and click drive options then click Format. This will only format the Windows volume so it can be recognized so you can install Windows on it. Then proceed with the installation of you’re choosing of Windows ®️

Cheers,

Nicholas 

Sorry you're ticked off. My guess is the drive in a 2012 iMac and the one in a 2018 iMac aren't the same. It's no doubt a hardware issue and I can't see Apple retrofitting 6 year old iMac's drives so a few people can run Boot Camp. I could be wrong. In the meantime you could run Windows as a virtual machine.

You're missing the point - I can't install Mojave without erasing my BootCamp partition. Period. And even if I back it up, I can't use BootCamp with Mohave on my mac. At all. Period.

From Apple/s Support Docs:

BootCamp Installer will not run on my particular mac under Mojave. So it's literally BoorCamp or Mojave, either/or.

I suggested starting a new discussion to avoid confusion with OP. If you have a 3TB Fusion drive with Windows installed, your Mojave upgrade should have failed.

It's fairly asinine that Apple couldn't accommodate this specific configuration. If I were you, I'd stick with High Sierra. I'm running a Mac Pro 5,1 with High Sierra and I've seen too many horror stories today that would directly affect me, most notably the fact that my wireless card would be useless after the "upgrade." Nope, no thanks.

I would guess this bug is related to the partition scheme for 3 TB fusion drives. But Apple should fix this soon to avoid loosing user trust. I've postponed my iMac Pro purchase until Apple corrected that for my iMac 27" late 2012 with 3 TB fusion drive.

I have a Mac Pro mid 2012 and Boot Camp was working fine on High Sierra, I use Window 7 ultimate on a separate disk for gaming.

I have now installed Mojave v 10.14 and the Boot Camp assistant doesn't work any more.

I have this message.

My Window drive doesn't show on reboot with Alt key pressed, neither it appear's on system pref > Choose startup disk.

The only thing that hase changed is Mac OS: (High Sierra -> Mojave), so I think Mojave is the only culprit !

cd

As I have already say on this forum, I don't think the problem is the drive. I have installed Windows 7 on a separate disk and Boot Camp was ok under High Sierra, I use TUXERA to gain access to the Windows drive from Mac OS.

Still waiting for a fix to Mojave from Apple ...

cd

The following isn't regarding 2012 iMacs but after spending time trawling the internet looking for a solution and trying all kinds of things, I have posted this here in the hope it helps someone else.

I spent a long time trying to get Boot Camp to behave on my late 2015 i5 iMac running Mojave but it just wouldnt get past the partitioning of the disk phase in BCA. It would error within a minute or two.

I then tried the manual route, successfully created a partition, booted into Windows using a bootable USB but then Windows had issues in the 'Copying Files' phase of the install and would error there too!

I tinkered a while and eventually broke my OSX install completely by accidentally deleting a partition of the Fusion Drive. Great.

As always, I have a Time Machine external drive plugged in at all times and decided to start again from scratch restoring a backup from 2 days before.

After a few hours, restore completed and everything was back where it had originally been.

Tried the BCA again and shock of the century it worked first time so I now have Windows 10 Pro and OSX Mojave running together like old friends.

The cure? I couldnt tell you, if I'm honest but if it worked for me, it may work for you!

Time Machine + start from scratch = Happy New Year!