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User profile for user: cburfield
cburfield Author
User level: Level 1
8 points

Failing to Partition in Boot Camp

I just got a new iMac yesterday (mid-2017 model with a 1TB fusion drive) and I have been trying to use Bootcamp assistant to install Windows 10. However, bootcamp is unable to partition the drive no matter what size I set the Windows partition at (and I have a total ~770 free GB out of which I would like to give Windows 200 GB). It tells me to run disk utility and that tells me everything is ok.


I've seen other discussions on here about bootcamp unable to partition fusion drives but I'm not sure if they fully apply to my situation. I would greatly appreciate it if anybody could help get past the partitioning step of bootcamp. Thanks!

Posted on Mar 3, 2018 8:43 AM

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14 replies
User profile for user: Loner T
Loner T
User level: Level 9
59,471 points

Mar 4, 2018 3:22 PM in response to cburfield

cburfield wrote:


I was able to create a 200 GB Fat-32 partition without any errors.


I guess this means I'll have to manually install?

This shows that High Sierra BC Assistant has bugs. 😉. You have two choices,


  • Remove the FAT partition and retry BC Assistant, or,
  • Create an EFI installer using Windows Media Creation Tool and use the existing partition. You will need to add BC drivers to the USB to ensure that the Apple hardware is supported during the boot process. Also, see Build your own Windows 10 Bootcamp USB Installer .
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User profile for user: kaplucker
kaplucker
User level: Level 1
59 points

Mar 3, 2018 9:14 AM in response to cburfield

I recently had a similar problem on my iMac. Apparently there can be a problem with bootcamp partitioning on a volume that has local Time Machine snapshots. To fix the issue, you need to delete all the local snapshots. Here is a site that details the process (or you can Google the subject for other sites):


https://ppolyzos.com/2017/10/20/how-to-manually-delete-local-snapshots-from-time -machines-backups/


Keep in mind the user account you are using when you do this has to be an administrator.


-kp

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User profile for user: cburfield
cburfield Author
User level: Level 1
8 points

Mar 3, 2018 3:20 PM in response to Loner T

I don't have Time Machine set up yet.


Results of diskutil list and diskutil cs list

/dev/disk0 (internal):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme 28.0 GB disk0

1: EFI EFI 314.6 MB disk0s1

2: Apple_CoreStorage Macintosh HD 27.6 GB disk0s2

3: Apple_Boot Boot OS X 134.2 MB disk0s3


/dev/disk1 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_CoreStorage Macintosh HD 899.6 GB disk1s2

3: Apple_Boot Recovery HD 100.4 GB disk1s3


/dev/disk2 (internal, virtual):

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Macintosh HD +926.2 GB disk2

Logical Volume on disk0s2, disk1s2

10C7D780-A2C0-4544-B40D-534FC3F1BD27

Unencrypted Fusion Drive


/dev/disk3 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: WINDOWS10 +15.5 GB disk3


CoreStorage logical volume groups (1 found)

|

+-- Logical Volume Group C98F4750-70A3-40FE-AA6D-21D88F12724D

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

Name: Macintosh HD

Status: Online

Size: 927142809600 B (927.1 GB)

Free Space: 454656 B (454.7 KB)

|

+-< Physical Volume 14B12519-7FC5-4EE4-B244-F2AB09CD17C3

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

| Index: 0

| Disk: disk0s2

| Status: Online

| Size: 27551166464 B (27.6 GB)

|

+-< Physical Volume 5443DDB4-82AB-4942-ABBD-00D6A48E5F15

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

| Index: 1

| Disk: disk1s2

| Status: Online

| Size: 899591643136 B (899.6 GB)

|

+-> Logical Volume Family 2AB14D5A-94D5-4386-BE23-56647D1A40AC

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

Encryption Type: None

|

+-> Logical Volume 10C7D780-A2C0-4544-B40D-534FC3F1BD27

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

Disk: disk2

Status: Online

Size (Total): 926226710528 B (926.2 GB)

Revertible: No

LV Name: Macintosh HD

Volume Name: Macintosh HD

Content Hint: Apple_HFS

LVG Type: Fusion, Sparse

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User profile for user: Loner T
Loner T
User level: Level 9
59,471 points

Mar 3, 2018 3:38 PM in response to cburfield

cburfield wrote:


I don't have Time Machine set up yet.


I see a Time Machine backup being created in the next couple of hours, in your immediate future. 😉

cburfield wrote:


Results of diskutil list and diskutil cs list


3: Apple_Boot Recovery HD 100.4 GB disk1s3

Notice the size of Recovery HD. This is a known issue in High Sierra. The safest method to use a TM backup/erase and rebuild Fusion drive/restore.

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User profile for user: Loner T
Loner T
User level: Level 9
59,471 points

Mar 3, 2018 3:57 PM in response to cburfield

You had a previous failure (one or more) when running BC Assistant, which caused the Recovery HD to become 100GB. BC Assistant requires contiguous disk space to create a partition and also relocate the current 100GB somewhere. The first failure reduces the contiguous space, and the second attempt wants some more contiguous space, which may no longer be available.


A TM backup/restore will give you larger contiguous space, and can be used to address the Recovery HD size issue, at the same time.

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User profile for user: cburfield
cburfield Author
User level: Level 1
8 points

Mar 4, 2018 6:35 AM in response to Loner T

I've rebuilt the fusion drive in recovery mode and restored from my TM backup. Without doing anything else to the machine I tried to partition the drive in bootcamp assistant and it failed at building a 200 GB partition.


Results of diskutil list and diskutil cs list after this failure:


/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_CoreStorage Macintosh HD 999.3 GB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3


/dev/disk1 (internal):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme 28.0 GB disk1

1: EFI EFI 314.6 MB disk1s1

2: Apple_CoreStorage Macintosh HD 27.6 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 +1.0 TB disk2

Logical Volume on disk0s2, disk1s2

45B38070-6F21-489F-BE4A-6C2487DD2769

Unencrypted Fusion Drive


/dev/disk3 (external, physical):

#: TYPE NAME SIZE IDENTIFIER

0: FDisk_partition_scheme *15.5 GB disk3

1: Windows_FAT_32 WINDOWS10 15.5 GB disk3s1


/dev/disk4 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: WINDOWS10 +15.5 GB disk4


diskutil cs list

CoreStorage logical volume groups (1 found)

|

+-- Logical Volume Group A02A2F45-F2A3-40B1-B3CC-07629CE07220

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

Name: Macintosh HD

Status: Online

Size: 1026896293888 B (1.0 TB)

Free Space: 151552 B (151.6 KB)

|

+-< Physical Volume 6BB862DF-7595-4A8F-AA96-88ED3EC726ED

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

| Index: 0

| Disk: disk0s2

| Status: Online

| Size: 999345127424 B (999.3 GB)

|

+-< Physical Volume 41FC2511-D968-4E11-A66A-E3E2C0E4DC76

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

| Index: 1

| Disk: disk1s2

| Status: Online

| Size: 27551166464 B (27.6 GB)

|

+-> Logical Volume Family 84125AA9-A786-49F5-B185-55EB2B2FEB3D

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

Encryption Type: None

|

+-> Logical Volume 45B38070-6F21-489F-BE4A-6C2487DD2769

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

Disk: disk2

Status: Online

Size (Total): 1025980497920 B (1.0 TB)

Revertible: No

LV Name: Macintosh HD

Volume Name: Macintosh HD

Content Hint: Apple_HFS

LVG Type: Fusion, Sparse

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User profile for user: Loner T
Loner T
User level: Level 9
59,471 points

Mar 4, 2018 6:42 AM in response to cburfield

cburfield wrote:



diskutil cs list

CoreStorage logical volume groups (1 found)

|

+-- Logical Volume Group A02A2F45-F2A3-40B1-B3CC-07629CE07220

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

Name: Macintosh HD

Status: Online

Size: 1026896293888 B (1.0 TB)

Free Space: 151552 B (151.6 KB)

|

+-< Physical Volume 6BB862DF-7595-4A8F-AA96-88ED3EC726ED

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

| Index: 0

| Disk: disk0s2

| Status: Online

| Size: 999345127424 B (999.3 GB)

|

+-< Physical Volume 41FC2511-D968-4E11-A66A-E3E2C0E4DC76

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

| Index: 1

| Disk: disk1s2

| Status: Online

| Size: 27551166464 B (27.6 GB)

Notice that your SSD (28GB) is at index 1, not 0. BC Assistant uses the disk at index 1 and can not exceed the underlying physical size of the disk. You have two choices, rebuild your Fusion drive, with the SSD at index 0, or manually partition using diskutil cs resizeStack commands.

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User profile for user: cburfield
cburfield Author
User level: Level 1
8 points

Mar 4, 2018 11:44 AM in response to Loner T

Ok, after second time of re-building the fusion drive and restoring from TM backup it still won't partition in boot camp. Error said there wasn't enough space, I was trying to create a 200 GB windows partition.


Results of diskutil list and diskutil cs list:


/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_CoreStorage Macintosh HD 999.3 GB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3


/dev/disk1 (internal):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme 28.0 GB disk1

1: EFI EFI 314.6 MB disk1s1

2: Apple_CoreStorage Macintosh HD 27.6 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 +1.0 TB disk2

Logical Volume on disk1s2, disk0s2

3F8F4B27-8ACA-4B54-9C17-C2EBE616C9D7

Unencrypted Fusion Drive



CoreStorage logical volume groups (1 found)

|

+-- Logical Volume Group A0E5D130-7E0F-44F2-8322-1FD1900BAB74

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

Name: Macintosh HD

Status: Online

Size: 1026896293888 B (1.0 TB)

Free Space: 151552 B (151.6 KB)

|

+-< Physical Volume 21ED35DF-CB32-4A17-A3A3-D6893342F287

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

| Index: 0

| Disk: disk1s2

| Status: Online

| Size: 27551166464 B (27.6 GB)

|

+-< Physical Volume FDA44C99-4837-4C65-9936-0855786F07AA

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

| Index: 1

| Disk: disk0s2

| Status: Online

| Size: 999345127424 B (999.3 GB)

|

+-> Logical Volume Family D04EBC4C-9C57-459A-BA6F-2F6AFC03259B

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

Encryption Type: None

|

+-> Logical Volume 3F8F4B27-8ACA-4B54-9C17-C2EBE616C9D7

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

Disk: disk2

Status: Online

Size (Total): 1025980497920 B (1.0 TB)

Revertible: No

LV Name: Macintosh HD

Volume Name: Macintosh HD

Content Hint: Apple_HFS

LVG Type: Fusion, Sparse

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Failing to Partition in Boot Camp

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