Boot Camp Won’t Work With macOS Mojave on 2012 27-Inch iMac With 3TB Hard Drive

[MacRumors]

Apple today shared a support document that will be of interest to customers who own a late 2012 27-inch iMac with a 3TB hard drive and are attempting to upgrade to the macOS Mojave update.

There is an issue on this iMac model that results in the following alert when attempting to install macOS Mojave: "Installation cannot proceed with Boot Camp configured."

To fix this problem, Apple says that customers with the 2012 27-inch iMac with 3TB hard drive will need to completely remove the Boot Camp partition using Boot Camp Assistant before macOS Mojave can be installed.

After upgrading to macOS Mojave, Boot Camp will not be able to be used to install Windows on these machines. No other iMac models appear to be affected by this issue.

Article Link: Boot Camp Won't Work With macOS Mojave on 2012 27-Inch iMac With 3TB Hard Drive

 

[computersteve]

Now if I owned this model i'd be pissed... I love bootcamp.

 

[Val-kyrie]

What???

How does this make any sense? Is Apple really listing the 2012 iMac as supporting Mojave then?

This seems like a serious oversight.

 

[macduke]

Good thing Apple designs their own hardware. The software only has to run on a limited subset of hardware so it's easier for them to test and focus on making a good user experience. /s

 

[techguy9]

That’s oddly specific. Hopefully it can be resolved soon.

 

[Mr. Retrofire]

That is what I call progress! Wonderful!

 

[dannyyankou]

Wait did Apple even try to fix this? Is a fix coming? Thank goodness I have a 2012 MacBook and not iMac.

 

[amadigan]

I seem to remember that BIOS emulation on EFI tends to not support drives over 2TB. Maybe that's the root cause? In that case, I wouldn't expect it to get resolved.

It's odd that Boot Camp would still be using BIOS emulation, I'm sure Windows 10 prefers EFI.

 

[Shoju]

No other iMac models appear to be affected by this issue.

I wish. I ran into the same message trying to install Mojave on my late 2014 iMac (27", Retina 5K, 3TB Fusion Drive). What's going on?! Don't tell me I won't be able to use Boot Camp again after updating to Mojave!?

 

[chucker23n1]

I seem to remember that BIOS emulation on EFI tends to not support drives over 2TB. Maybe that's the root cause? In that case, I wouldn't expect it to get resolved.

It's odd that Boot Camp would still be using BIOS emulation, I'm sure Windows 10 prefers EFI.

This is probably why. The machine is probably too old to have an EFI compatible with Windows, and they probably don’t want to special-case the MBR emulation to move Boot Camp in front of APFS.

 

[lec0rsaire]

Why not buy an external SSD and install it on that? You can use WintoUSB. If you don’t have access to a Windows machine download virtual box or VMware trial and give it a shot. It that doesn’t work then I guess these 2012 27” iMac users are SOL.

Also, if you’re brave just replace the 3TB drive with a 1TB SSD or something. Unfortunately it’s a lot of work and you can end up damaging the machine if you f up like Linus did with his iMac Pro.

9to5mac has a good tutorial on YT on how to install Win 10 on an external SSD if you need instructions.

 

[Pakaku]

I seem to remember that BIOS emulation on EFI tends to not support drives over 2TB. Maybe that's the root cause? In that case, I wouldn't expect it to get resolved.

It's odd that Boot Camp would still be using BIOS emulation, I'm sure Windows 10 prefers EFI.

If that was the case, Boot Camp wouldn't have worked at all before installing Mojave:

To fix this problem, Apple says that customers with the 2012 27-inch iMac with 3TB hard drive will need to completely remove the Boot Camp partition using Boot Camp Assistant before macOS Mojave can be installed.

So this sounds like a Mojave bug, and I wonder if just creating a basic fat32 partition through Disk Utility and installing Windows without Boot Camp (and letting it format the fat drive to NTFS in the process) would work just fine

 

[neek]

Not the only model affected. I have a 2013 iMac with Bootcamp on a Fusion drive and Mojave happily installed... it just broke my Bootcamp in the process.

https://forums.macrumors.com/threads/mojave-breaks-bootcamp-on-fusion-drive.2142473/
[doublepost=1537822253][/doublepost]

I seem to remember that BIOS emulation on EFI tends to not support drives over 2TB. Maybe that's the root cause? In that case, I wouldn't expect it to get resolved.

It's odd that Boot Camp would still be using BIOS emulation, I'm sure Windows 10 prefers EFI.

Boot Camp on 3 TB Fusion drives had to do a lot of voodoo. The start of the Windows partition had to be within the first 2 TB of the disk. High Sierra did some Core Storage tricks and put the Windows volume in the middle and had HFS+ partitions around it.

This is how my partition looked (when it worked):

 

[lec0rsaire]

I wish. I ran into the same message trying to install Mojave on my late 2014 iMac (27", Retina 5K, 3TB Fusion Drive). What's going on?! Don't tell me I won't be able to use Boot Camp again after updating to Mojave!?

Try external SSD. It should be as fast if not faster than the SSHD setup.

 

[FourDegrees]

Maybe a move to Virtual Box is the way to go then? It’s free and easy enough to set up.

 

[Berti10]

I wish. I ran into the same message trying to install Mojave on my late 2014 iMac (27", Retina 5K, 3TB Fusion Drive). What's going on?! Don't tell me I won't be able to use Boot Camp again after updating to Mojave!?

This is My exact configuration and it is installing for over 3h (bet it is the conversion to APFS). I‘ll let you know of it works. Grüße aus Hamburg

 

[Onexy]

It just works.

 

[sesnir]

FYI, this applies to the Late-2013 27" iMac also...

 

[Shoju]

Try external SSD. It should be as fast if not faster than the SSHD setup.

Well this means I need to invest in new hardware, though. Not something I planned simply to be able to update to the latest macOS...
Just to clarify, you suggest to put Mojave on an external SSD?

 

[now i see it]

OS updates are risky and usually break a few things. Not surprised at all.

 

[Shoju]

This is My exact configuration and it is installing for over 3h (bet it is the conversion to APFS). I‘ll let you know of it works. Grüße aus Hamburg

But did you have a Boot Camp partition installed as well? I didn't even come to installing it as the installer wants the Boot Camp partition removed before installation even starts...
Grüße aus Berlin!

 

[Berti10]

But did you have a Boot Camp partition installed as well? I didn't even come to installing it as the installer wants the Boot Camp partition removed before installation even starts...
Grüße aus Berlin!

Sonst wäre mein Post ja irgendwie witzlos ;P
I have 3TB Fusion Drive and 100 GB For Boot Camp. To Play GTA V I further partitioned the drive to a Second 100GB portion. Installed with noch warning sign. ...but still does. Now over 4h and the indicatior did not move just a Pixel.

 

[ikir]

Good thing Apple designs their own hardware. The software only has to run on a limited subset of hardware so it's easier for them to test and focus on making a good user experience. /s

It is just a single model with a custom CTO hard drive, incredibly rare. If possible they will fix it, it could be related to how partition are handled, specific chipset and go on

 

[Shoju]

Sonst wäre mein Post ja irgendwie witzlos ;P

Da hast du recht...

I have 3TB Fusion Drive and 100 GB For Boot Camp. To Play GTA V I further partitioned the drive to a Second 100GB portion. Installed with noch warning sign. ...but still does. Now over 4h and the indicatior did not move just a Pixel.

That's strange. So on mine the installation process won't even start but on yours it doesn't actually spit out a warning sign... Makes it look like a bug. Interesting - keep me/us posted!

 

[noxivs]

I have that exact configuration. 3TB Fusion on a late 2012 iMac. And I use the Bootcamp partition for gaming. I tried installing a couple of betas, of course did not work. I asked on this very forum about it and no one even replied. It is a specific config so I understand but Apple not telling about that right from the beginning is a fail. Now it is officially out and I will never get to install Windows on it? At least give us a ballpark? Being forced to delete the Bootcamp is painful enough to begin with. I keep this machine mostly to play on Bootcamp but I want my Mojave too!!
[doublepost=1537829829][/doublepost]

Maybe a move to Virtual Box is the way to go then? It’s free and easy enough to set up.

For many of us Mac users, Bootcamp is only good for playing games. And VM and gaming don't go hand in hand