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Question: Cannot decrease Windows partition size to less than 1058 GB

OS: macOS Sierra, Version 10.12.6

Model: iMac (27-inch, Late 2012)

Processor: 3.4 GHz Intel Core i7

Memory: 16 GB 1600 MHz DDR3

Startup Disk Storage: 3.11 TB

Graphics: NVIDIA GeForce GTX 680MX 2048 MB

Boot Camp Assistant: Version 6.1.0 (6050.60.1)


I have already created an install disk and downloaded the latest Windows support software, but I have a problem when I try to add a Windows partition to the startup disk. The slider bar does not allow me to make the partition any smaller than 1058 GB, which I know for a fact is WAY more than you need for a partition. Also, I only have about 313 GB available on my startup disk, so I couldn't set up a partition with a size this big, anyway, so why is it asking me to do so? I know the problem isn't in the ISO image or the version of Windows I'm trying to install; I tried two different ISO files (one for Windows 8.1, and one for Windows 10) and they both had this problem. In the image below, the divider on the slider bar is dragged as far to the right as possible.

User uploaded file

I believe the problem is in Boot Camp Assistant itself, because this slider bar seems really, really broken, and not just because of the 1058 GB minimum. For example, when you drag the divider, the partition sizes don't increase/decrease by increments of 1 GB. Rather, the size will apparently not change, then suddenly jump by a large amount (e.g. from 1058 GB to 3106 GB, or from 3106 GB to 5153 GB, as shown in the next four images. At this point, the partition size would be larger than the amount of storage in the entire startup disk).

User uploaded fileUser uploaded file

User uploaded file

User uploaded file

I can even drag the divider of the slider bar so far to the left that it leaves the window.


User uploaded file

User uploaded file


User uploaded file


User uploaded file

With all of this, I think it's safe to say that the application itself is pretty broken. Is there any way to uninstall, then reinstall Boot Camp Assistant without completely reinstalling macOS? Or is there another solution that you guys suggest? I included some tech specs at the top if any of those help.


Final note: I haven't actually tried to install the partition, because if it was successful, and the size of the partition was as big as Boot Camp Assistant says it is, there would obviously be no room for over 500 GB of the files in the Mac partition.

iMac, macOS Sierra (10.12.6), null

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Nov 11, 2017 5:45 PM in response to Loner T In response to Loner T

From diskutil list

/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 3.0 TB disk1s2


3: Apple_Boot Recovery HD 650.0 MB
disk1s3


/dev/disk2 (internal, virtual):


#: TYPE NAME SIZE IDENTIFIER


0: Apple_HFS Macintosh HD +3.1 TB disk2

Logical Volume on disk0s2, disk1s2

A73082BE-C450-44D6-BE6D-92C37182E7AE

Unencrypted Fusion Drive


/dev/disk3 (external, physical):


#: TYPE NAME SIZE IDENTIFIER


0: GUID_partition_scheme *4.0 TB disk3


1: EFI EFI 314.6 MB
disk3s1


2: Apple_HFS My Book 4.0 TB disk3s2


/dev/disk4 (external, physical):


#: TYPE NAME SIZE IDENTIFIER


0: FDisk_partition_scheme *32.0 GB disk4


1: DOS_FAT_32 WININSTALL 32.0 GB disk4s1


/dev/disk5 (disk image):


#: TYPE NAME SIZE IDENTIFIER


0: IR5_CCSA_X64FRE_EN-... +4.3 GB disk5


/dev/disk6 (disk image):


#: TYPE NAME SIZE IDENTIFIER


0: Boot Camp +2.8 GB disk6

From diskutil cs list

CoreStorage logical volume groups (1 found)

|

+-- Logical Volume Group AF994E04-C4E9-4B5E-AA2F-358D14EE484A

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

Name: Macintosh HD

Status: Online

Size: 3120722075648 B (3.1 TB)

Free Space:
114688 B (114.7 KB)

|

+-< Physical Volume 2A17E9A7-66D9-4813-AC93-055254F1C190

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

|
Index: 0

|
Disk: disk0s2

|
Status:
Online

|
Size: 120988852224 B (121.0 GB)

|

+-< Physical Volume 015DDA11-E6C3-411A-A094-8F59D7B75797

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

|
Index: 1

|
Disk: disk1s2

|
Status:
Online

|
Size: 2999733223424 B (3.0 TB)

|

+-> Logical Volume Family 1D90F443-DCF7-41E9-8FA3-81E8542FA48F

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

Encryption Type: None

|

+-> Logical Volume A73082BE-C450-44D6-BE6D-92C37182E7AE

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

Disk: disk2

Status: Online

Size (Total): 3106191572992 B (3.1 TB)

Revertible: No

LV Name: Macintosh HD

Volume Name: Macintosh HD

Content Hint: Apple_HFS

LVG Type: Fusion, Sparse

Nov 11, 2017 5:45 PM

Reply Helpful

Nov 11, 2017 6:03 PM in response to CourtOfTheCrimsonKing In response to CourtOfTheCrimsonKing

Your CS looks fine. Please remove the 4TB disk3 and connect it only after Windows is fully installed.


Run

How to reset the System Management Controller (SMC) on your Mac - Apple Support

How to reset NVRAM on your Mac - Apple Support


What is the version of Windows you want to install?

Nov 11, 2017 6:03 PM

Reply Helpful

Nov 11, 2017 6:51 PM in response to Loner T In response to Loner T

I want to install Windows 10. I used the ISO file provided by the official Microsoft website to make the install disk. When I got the error, I used an ISO file for Windows 8.1 instead (also provided by the Microsoft website), but I got the same error. I would prefer Windows 10, and, as previously mentioned, I'm pretty sure the OS version isn't the problem here.


Also, none of the instructions that you gave me worked. I removed disk3 (that's just used for Time Machine backups) and I followed the instructions of those two articles, but the slider bar remains the same.

Nov 11, 2017 6:51 PM

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Nov 11, 2017 7:27 PM in response to Loner T In response to Loner T

Started partition map repair on disk0

Checking prerequisites

Checking the partition list

Adjusting partition map to fit whole disk as required

Checking for an EFI system partition

Checking the EFI system partition's size

Checking the EFI system partition's file system

Checking the EFI system partition's folder content

Checking all HFS data partition loader spaces

Checking booter partitions

Checking booter partition disk0s3

Verifying file system

Checking Journaled HFS Plus volume

Checking extents overflow file

Checking catalog file

Checking multi-linked files

Checking catalog hierarchy

Checking extended attributes file

Checking volume bitmap

Checking volume information

The volume Boot OS X appears to be OK

File system check exit code is 0

Reviewing boot support loaders

Checking Core Storage Physical Volume partitions

Verifying storage system

Checking volume

disk1s2: Scan for Volume Headers

disk0s2: Scan for Volume Headers

disk1s2: Scan for Disk Labels

disk0s2: Scan for Disk Labels

Logical Volume Group AF994E04-C4E9-4B5E-AA2F-358D14EE484A spans 2 devices

disk0s2+disk1s2: Scan for Metadata Volume

Logical Volume Group has a 4481 MB Metadata Volume with double redundancy

Start scanning metadata for a valid checkpoint

Load and verify Segment Headers

Load and verify Checkpoint Payload

Load and verify Transaction Segment

Load and verify Transaction Segment

Load and verify Transaction Segment

Load and verify Transaction Segment

Load and verify Transaction Segment

Load and verify Transaction Segment

Incorporate 5 newer non-checkpoint transactions

Load and verify Virtual Address Table

Load and verify Segment Usage Table

Load and verify Metadata Superblock

Load and verify Logical Volumes B-Trees

Logical Volume Group contains 1 Logical Volume

Load and verify 1D90F443-DCF7-41E9-8FA3-81E8542FA48F

Load and verify A73082BE-C450-44D6-BE6D-92C37182E7AE

Load and verify Freespace Summary

Load and verify Block Accounting

Load and verify Live Virtual Addresses

Newest transaction commit checkpoint is valid

Load and verify Segment Cleaning

The volume AF994E04-C4E9-4B5E-AA2F-358D14EE484A appears to be OK

Storage system check exit code is 0

Repairing storage system

The volume disk1s2+disk0s2 cannot be repaired when it is in use

Checking volume

disk1s2: Scan for Volume Headers

disk0s2: Scan for Volume Headers

disk1s2: Scan for Disk Labels

disk0s2: Scan for Disk Labels

Logical Volume Group AF994E04-C4E9-4B5E-AA2F-358D14EE484A spans 2 devices

disk0s2+disk1s2: Scan for Metadata Volume

Logical Volume Group has a 4481 MB Metadata Volume with double redundancy

Start scanning metadata for a valid checkpoint

Load and verify Segment Headers

Load and verify Checkpoint Payload

Load and verify Transaction Segment

Load and verify Transaction Segment

Load and verify Transaction Segment

Load and verify Transaction Segment

Load and verify Transaction Segment

Load and verify Transaction Segment

Load and verify Transaction Segment

Incorporate 6 newer non-checkpoint transactions

Load and verify Virtual Address Table

Load and verify Segment Usage Table

Load and verify Metadata Superblock

Load and verify Logical Volumes B-Trees

Logical Volume Group contains 1 Logical Volume

Load and verify 1D90F443-DCF7-41E9-8FA3-81E8542FA48F

Load and verify A73082BE-C450-44D6-BE6D-92C37182E7AE

Load and verify Freespace Summary

Load and verify Block Accounting

Load and verify Live Virtual Addresses

Newest transaction commit checkpoint is valid

Load and verify Segment Cleaning

The volume AF994E04-C4E9-4B5E-AA2F-358D14EE484A appears to be OK

Storage system check exit code is 0

Updating Windows boot.ini files as required

The partition map appears to be OK

Finished partition map repair on disk0

Nov 11, 2017 7:27 PM

Reply Helpful

Nov 12, 2017 4:45 AM in response to CourtOfTheCrimsonKing In response to CourtOfTheCrimsonKing

The point of the exercise is to validate if DU gives the same errors as does BCA, to decide which one is at fault. If DU works and you were able to create a partition of the size of you want without any issues, then it can be used as a destination for the Windows installation with some additional steps to create a MBR for BIOS support.


Can you post the output of


diskutil list


for validation of the FAT partition?

Nov 12, 2017 4:45 AM

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Nov 12, 2017 8:36 AM in response to Loner T In response to Loner T

/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 2.9 TB disk1s2

3: Apple_Boot Recovery HD 650.0 MB
disk1s3

4: Microsoft Basic Data B C P 89.5 GB disk1s4


/dev/disk2 (internal, virtual):

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Macintosh HD +3.0 TB disk2

Logical Volume on disk0s2, disk1s2

A73082BE-C450-44D6-BE6D-92C37182E7AE

Unencrypted Fusion Drive

Nov 12, 2017 8:36 AM

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Nov 12, 2017 8:50 AM in response to CourtOfTheCrimsonKing In response to CourtOfTheCrimsonKing

The hybrid MBR needed on a 2012 iMac for legacy BIOS cannot accommodate a BC partition which starts outside the 2TB address and is less than 1TB. Can you post the output of


sudo fdisk /dev/disk1


BTW, I assume you have heard - King Crimson In The Court Of The Crimson King live - YouTube .

Nov 12, 2017 8:50 AM

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User profile for user: CourtOfTheCrimsonKing

Question: Cannot decrease Windows partition size to less than 1058 GB