Windows 10 Boot Camp install won't let me install on BOOTCAMP partition on Mac Pro with SSD drive

Your Fusion drive is incorrect and is causing BC to fail. You have the 1TB HDD as disk0 at index 0, it should be index 1. The SSD must always be index 0, otherwise your OSX performance and Fusion functionality is incorrect. You need to backup OSX, boot into Internet Recovery and rebuild your Fusion drive correctly before attempting a Windows installation.

I just did a full rebuild of my Fusion drive in Recovery mode. and Disk util rebuild it as per apple default with SSD as disk 1 and my 3TB as disk 0

So i wouldn't recommend above from Loner. as i dont think Disk util will rebuild it in any other way.

Edit: Based on what Loner T just wrote, this howto may be incorrect !!!

By the way, when someone realises to mess fusion drive partitions, there is a way how to revert everything to original state. Following steps worked for me (late 2015 iMac 2TB fusion). You will LOOSE EVERY DATA ON OUR MAC so backup first!

0) delete any partitions previously created by Windows installation or boot camp assistant if any

1) cmd+r on boot after boot-up sound, for 4 secs, recovery screen appears after minute

2) Top bar -> Utilities -> Terminal

3) diskutil cs list

4) select and copy logical volume ID at the top (in my case it was 50FBAD7C-8655-43F2-8B85-E60DDA4A5894 )

5) diskutil cs delete <paste logical volume ID>

example: diskutil cs delete 50FBAD7C-8655-43F2-8B85-E60DDA4A5894

6) last output should be "Finished CoreStorage operation"

7) diskutil list

8) You should see that APPLE HDD ST20 location (/dev/disk0 in my case) and APPLE SSD SM01 (/dev/disk1 in my case), use them in correct order in next command as you can see

9) diskutil cs create Macintosh\ HD <HDD> <SSD>

example: diskutil cs create Macintosh\ HD disk0 disk1

10) last output line should be "Finished CoreStorage operation"

11) diskutil cs list

12) select and copy logical volume ID at the top (in my case it was 28EB112E-C9D8-444D-8BAC-7876B768740A )

13) diskutil cs createVolume <paste logical volume ID> jhfs+ Macintosh\ HD 100%

example: diskutil cs createVolume 28EB112E-C9D8-444D-8BAC-7876B768740A jhfs+ Macintosh\ HD 100%

14) close terminal (corner red X button, when I did different approach by typing exit, recovery menu didn't recover)

15) choose Disk Utility from recovery list

16) you should see Fusion drive with macintosh HD only

17) close Disk Utility (corner red X button)

18) chose Reinstall OS X

19) follow reinstall steps

If what you're saying is correct, howto I just wrote is incorrect. I was instrued by official Apple senior support and this is the result. It's not easy for me to wipe everything now. Can anyone please post correct post how to rebuild fusion drive correctly? I bought this iMac with exactly this setup (dev0 HDD, dev1 SSD) so it was default configuration.

larspj wrote:

I just did a full rebuild of my Fusion drive in Recovery mode. and Disk util rebuild it as per apple default with SSD as disk 1 and my 3TB as disk 0

So i wouldn't recommend above from Loner. as i dont think Disk util will rebuild it in any other way.

A CS PV at index 0 is fast disk designed to off-load LRU blocks to disks at index 1...n. If you have it any other way. it is invalid. Please see the IO tests at http://jolly.jinx.de/teclog/2012.10.20.fusion-drive-on-older-macs-yes.html .

Diskutil will rebuild a CS anyway you want it to. Please also see OSX and Bootcamp discussion .

You are confusing disk0 and disk1 with CS PV indices. disk0 and disk1 are based on probes by controllers to discover disks. They have no relationship with the CS index. Once a CS is built, the order of discovery may change and disk1 may be the SSD. The CS unit stores the indices and manages data block movement based on CS PV Indices, not the diskN numbering. The instructions you wrote need to account for the ordering of the fast vs slow disks. As I posted earlier, see the IO test results. You want the slower disks at index 1...n not at 0. If you have multiple SSDs, you must ensure that the faster disks have lower indices than any of the slowest disks.

I have had to fix the Apple instructions over the years. Please see the links I have posted.

I tried to understand both links you sent but I still don't follow why SSD should be always the first. Can you please write a little howto how we can rebuilt partitions so the SSD will be first? I'll try.

Please see this example El Capitan Upgrade bootcamp not showing Windows 10 .

CoreStorage logical volume groups (1 found)

|

+-- Logical Volume Group B24CB135-A898-4C6F-B85B-EC50E15204A5

=========================================================

Name: Mac

Status: Online

Size: 2120528027648 B (2.1 TB)

Free Space: 114688 B (114.7 KB)

|

+-< Physical Volume 78B4C325-6D0A-4B97-AF1B-FABD818E60E7

| ----------------------------------------------------

| Index: 0

| Disk: disk1s2

| Status: Online

| Size: 120988852224 B (121.0 GB)

|

+-< Physical Volume AAB666F7-C010-4AEA-9660-3DF270165B46

| ----------------------------------------------------

| Index: 1

| Disk: disk0s2

| Status: Online

| Size: 1999539175424 B (2.0 TB)

|

+-> Logical Volume Family 8386538B-8A68-46A2-A10C-73B301A1FA6A

----------------------------------------------------------

Encryption Type: None

|

+-> Logical Volume E4CC4C1A-754D-4F25-90C8-9C622246CE9B

---------------------------------------------------

Disk: disk2

Status: Online

Size (Total): 2114672656384 B (2.1 TB)

Revertible: No

LV Name: Mac

Volume Name: Mac

Content Hint: Apple_HFS

LVG Type: Fusion, Sparse

Summary: It is possible to change disk order, diskutil cs create <DataHDDFriendlyName> <SSD> <HDD> is the key (Late mac 27" 2015 with fusion drive 2TB). My previous numbered howto here is therefore correct except this one point where as Loner T correctly wrote. Let's see if windows will install...

And no it doesn't. Same issue

How did you get Drive0: Partition 5? It should be partition 4.

Can you post your diskutil list output?

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *2.0 TB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_CoreStorage Macintosh HD 1.3 TB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s6

4: Microsoft Basic Data OSXRESERVED 8.0 GB disk0s4

5: Microsoft Basic Data BOOTCAMP 651.7 GB disk0s5

/dev/disk1 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *121.3 GB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_CoreStorage Macintosh HD 121.0 GB disk1s2

3: Apple_Boot Boot OS X 134.2 MB disk1s3

/dev/disk2 (internal, virtual):

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Macintosh HD +1.5 TB disk2

Logical Volume on disk1s2, disk0s2

C63A2632-ED74-4AEB-998E-3265C2333025

Unencrypted Fusion Drive

/dev/disk4 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: ESD-ISO +3.5 GB disk4

New bootcamp on iMac doesn't give you 3 choices anymore. It creates partition with windows installation. This is listed while bootcamp is preparing windows to install. Normally, 4 and 5 are not there.

Please post the output of sudo fdisk /dev/disk0 . The OSXRESERVED being present is a good sign. Can you mount it and check what files are present?

Filips-iMac:Contents plysovejkaktus$ sudo fdisk /dev/disk0

Password:

Disk: /dev/disk0 geometry: 243201/255/63 [3907029168 sectors]

Signature: 0xAA55

Starting Ending

#: id cyl hd sec - cyl hd sec [ start - size]

------------------------------------------------------------------------

1: EE 1023 254 63 - 1023 254 63 [ 1 - 3907029167] <Unknown ID>

2: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

3: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

While bootcamp is installing iso onto OSXRESERVED before automatic restart. Volume is mounted while bootcamp is filling it with data which are then being used for installation:

Filips-iMac:Contents plysovejkaktus$ df -h

Filesystem Size Used Avail Capacity iused ifree %iused Mounted on

/dev/disk2 1.6Ti 29Gi 1.6Ti 2% 7757849 426080037 2% /

devfs 188Ki 188Ki 0Bi 100% 651 0 100% /dev

map -hosts 0Bi 0Bi 0Bi 100% 0 0 100% /net

map auto_home 0Bi 0Bi 0Bi 100% 0 0 100% /home

/dev/disk0s4 7.4Gi 4.2Gi 3.2Gi 57% 0 0 100% /Volumes/OSXRESERVED

/dev/disk4 1.1Gi 1.1Gi 0Bi 100% 0 0 100% /Volumes/Boot Camp

After automatic restart and unsuccessfull windows installation, I can't longer the partition (even it's there, I can access it via bootloader and run again):

Filips-iMac:/ plysovejkaktus$ df -h

Filesystem Size Used Avail Capacity iused ifree %iused Mounted on

/dev/disk2 1.6Ti 29Gi 1.6Ti 2% 7745063 426092823 2% /

devfs 185Ki 185Ki 0Bi 100% 641 0 100% /dev

map -hosts 0Bi 0Bi 0Bi 100% 0 0 100% /net

map auto_home 0Bi 0Bi 0Bi 100% 0 0 100% /home

/dev/disk0s5 307Gi 131Mi 307Gi 1% 27 321810333 0% /Volumes/Untitled

ls /dev/disk*

/dev/disk0 /dev/disk0s2 /dev/disk0s5 /dev/disk1s1 /dev/disk1s3

/dev/disk0s1 /dev/disk0s3 /dev/disk1 /dev/disk1s2 /dev/disk2

Here's filelist of OSXRESERVERD as prepared by BootCamp for Windows 10 installation:

https://drive.google.com/file/d/0B9b7ONnBwzfjNm1DOUFJbExwMnM/view?usp=sharing