How to restore partition layout of my 1TB Fusion Drive?

Question

How to restore partition layout of my 1TB Fusion Drive?

Hi there,

I purchased a Late 2013 iMac 27" with a 1 TB Fusion Drive. I tried to install Windows 8.1 without Bootcamp. My Installation with Bootcamp didn't work - there was an error stating that Windows Installation was not able to prepare for the next step of the installation - so I partitioned manually via OS X Disk Utility (resizing the Macintosh HD) and tried to install to the unused disk space - okay my mistake. This somehow didn't work either. Now I have the following situation: The Disk Utility shows the following partition layout:

Macintosh HD 779,53 GB

Unused disk space 220,33 GB

I am not able to resize the Macintosh HD to use the unused disk space (original partition layout). There is no option for this. The partition layout option is greyed out. When I try to create a second partition of the unused space and proceed, nothing happens (protocol states preparing to partition: „APPLE HDD ST1000DM003 Media“ - nothing more). The operation will not finish. Next to the partition scheme is the following information (translated from german): "For a new partition layout the whole capacity of the Fusion Drive won't be available." The whole Macintosh HD now has a capacity of 900,52GB (Disk Utility).

What can I do to restore to the original partition layout of my Fusion Drive which had a capacity of about 1,1TB?

Thank you for your help!

Chris

iMac, OS X Mavericks (10.9.4)

Posted on Aug 11, 2014 1:38 PM

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Answer 1

Loner T

Level 9

59,471 points

Aug 11, 2014 1:44 PM in response to supersonic_jet

Windows 8.1 can be installed either via the traditional Bootcamp (CSM-BIOS) or using EFI on Late 2013 machines. The following is confusing on what you tried.

I tried to install Windows 8.1 without Bootcamp. My Installation with Bootcamp didn't work

What issues did you have with Bootcamp/Windows 8.1 installation?

Boot Camp 5.1: Frequently asked questions

Do computers that come with a Fusion Drive support Boot Camp?

Yes. Use the Boot Camp Assistant to create a Windows partition and install Boot Camp. The Windows partition will exist on the hard disk drive, not the Flash drive, and is not part of Fusion Drive Logical Volume Group. 3TB Fusion Drive configurations need to update to OS X Mountain Lion v10.8.3 or later to install Windows 8. See iMac (27-inch, Late 2012): Boot Camp alert with 3TB hard drive for more information.

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Answer 2

Aug 11, 2014 1:55 PM in response to Loner T

Hi Loner T,

during Windows Installation (with Bootcamp preparation) I choose the partition with the name BOOTCAMP as target for Windows. But there was an error message that this was not possible because of (unfortunately exact message i forgot) MBR and not EFI something... :-(

Where could I have chosen the different methods?

Chris

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Answer 3

Loner T

Level 9

59,471 points

Aug 11, 2014 2:27 PM in response to supersonic_jet

If the Bootcamp Assistant did not create the partition (and it does other things in the background), it will not let you install Windows (this is the CSM-BIOS method) and user has no control. For this method to work, the only partitions on your original pre-Bootcamp single-disk (Fusion drives may have two physical drives but they are fused into a single disk) system should be EFI, Recovery HD and OSX. This method uses a Hybrid MBR and CSM-BIOS. In the Bootcamp FAQ, a CSM-BIOS installation uses only the HDD (not the SSD)

The Windows partition will exist on the hard disk drive, not the Flash drive, and is not part of Fusion Drive Logical Volume Group.

If you do not allow Bootcamp do the partitioning but use Disk Utility and create Free Space, and use the following steps, you can use the EFI side. If you want an EFI installation, and have built a USB with Bootcamp drivers and the Windows ISO (or DVD) then when your machine reboots and starts the Windows installation, holding the ALT key may show you additional entries, which will probably be OSX, Recovery HD, Windows, EFI Boot.

If you select EFI boot here, than you are not using CSM-BIOS, but EFI. It has some advantages over the traditional method, but some older Macs may have issues with Sound and Graphics when using the EFI method, but yours is new enough.

If you want to try the EFI route, please ask.

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Answer 4

Aug 11, 2014 2:59 PM in response to Loner T

Thank you very much for the information you provided!

I tried now to install to the unused Disk Space with the current partition layout. When restarting with ALT I chose EFI Boot, followed the Windows Installation steps and chose unused disk space of 220GB as target. An new error occurred: it states the partition is no NTFS format, I should reformat to FAT 32 an try again (this confused me: why is it complaining it's not NTFS and in the next steps asks to reformat to FAT32). As I went back to Mavericks Disk Utility I found the following partition layout:

Macintosh HD with 779,53 GB

an the the 220GB of unused space was partitioned as follows:

disk1s4 with 134,2 MB

disk1s6 with 314,6 MB

Untitled (NTFS) 218,98 GB

I wonder how to start from scratch again?

Chris

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Answer 5

Loner T

Level 9

59,471 points

Aug 11, 2014 4:19 PM in response to supersonic_jet

When I installed Windows8.1, it wanted it to be Free space with not formatting and the installer formatted it into two. One Microsoft Reserved Partition, the other was formatted as NTFS. If you execute diskutil list disk1, it should show you what it has.

Can you post the output of diskutil list disk1 before anything is deleted?

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Answer 6

Aug 12, 2014 12:38 AM in response to Loner T

Hi Loner,

this is the output right now:

diskutil list disk1

/dev/disk1

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_CoreStorage 779.5 GB disk1s2

3: Apple_Boot Recovery HD 650.0 MB disk1s3

4: Microsoft Reserved 134.2 MB disk1s4

5: EFI NO NAME 104.9 MB disk1s5

6: DE94BBA4-06D1-4D40-A16A-BFD50179D6AC 314.6 MB disk1s6

7: EFI NO NAME 104.9 MB disk1s7

8: Microsoft Basic Data 219.0 GB disk1s8

Chris

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Answer 7

Loner T

Level 9

59,471 points

Aug 12, 2014 2:11 AM in response to supersonic_jet

On disk1, you have in order, Apple EFI, Apple CoreStorage (Fusion drive part), Recovery HD, MSR, Microsoft EFI, Microsoft Recovery, Microsoft EFI (part 2 - this makes no sense to be here - did you have an installation failure using EFI mode once), Microsoft FAT/NTFS (C:).

The SSD part needs to be looked at as well.

Please post the output of

1. diskutil list

2. diskutil list disk0

3. sudo gpt -vv -r show /dev/disk0

4. sudo gpt -vv -r show /dev/disk1

If you want to see a bit more detail this can help you enable DU in debug mode - http://macs.about.com/od/usingyourmac/qt/Enable-Disk-Utilitys-Debug-Menu.htm

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Answer 8

Aug 12, 2014 2:23 AM in response to Loner T

Yes, I think my first attempt was also in EFI mode, this could have resulted in the second EFI part.

Here are the requested outputs:

diskutil list

/dev/disk0

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *121.3 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_CoreStorage 121.0 GB disk0s2

3: Apple_Boot Boot OS X 134.2 MB disk0s3

/dev/disk1

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_CoreStorage 779.5 GB disk1s2

3: Apple_Boot Recovery HD 650.0 MB disk1s3

4: Microsoft Reserved 134.2 MB disk1s4

5: EFI NO NAME 104.9 MB disk1s5

6: DE94BBA4-06D1-4D40-A16A-BFD50179D6AC 314.6 MB disk1s6

7: EFI NO NAME 104.9 MB disk1s7

8: Microsoft Basic Data 219.0 GB disk1s8

/dev/disk2

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Macintosh HD *894.3 GB disk2

diskutil list disk0

/dev/disk0

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *121.3 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_CoreStorage 121.0 GB disk0s2

3: Apple_Boot Boot OS X 134.2 MB disk0s3

sudo gpt -vv -r show /dev/disk0

Password:

gpt show: /dev/disk0: mediasize=121332826112; sectorsize=512; blocks=236978176

gpt show: /dev/disk0: PMBR at sector 0

gpt show: /dev/disk0: Pri GPT at sector 1

gpt show: /dev/disk0: Sec GPT at sector 236978175

start size index contents

0 1 PMBR

1 1 Pri GPT header

2 32 Pri GPT table

34 6

40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

409640 236306352 2 GPT part - 53746F72-6167-11AA-AA11-00306543ECAC

236715992 262144 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

236978136 7

236978143 32 Sec GPT table

236978175 1 Sec GPT header

sudo gpt -vv -r show /dev/disk1

gpt show: /dev/disk1: mediasize=1000204886016; sectorsize=512; blocks=1953525168

gpt show: /dev/disk1: PMBR at sector 0

gpt show: /dev/disk1: Pri GPT at sector 1

gpt show: /dev/disk1: Sec GPT at sector 1953525167

start size index contents

0 1 PMBR

1 1 Pri GPT header

2 32 Pri GPT table

34 6

40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

409640 1522514312 2 GPT part - 53746F72-6167-11AA-AA11-00306543ECAC

1522923952 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

1524193488 1840

1524195328 262144 4 GPT part - E3C9E316-0B5C-4DB8-817D-F92DF00215AE

1524457472 352256

1524809728 204800 5 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

1525014528 614400 6 GPT part - DE94BBA4-06D1-4D40-A16A-BFD50179D6AC

1525628928 204800 7 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

1525833728 427689984 8 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

1953523712 1423

1953525135 32 Sec GPT table

1953525167 1 Sec GPT header

Thanks for your help!

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Answer 9

Loner T

Level 9

59,471 points

Aug 12, 2014 5:24 AM in response to supersonic_jet

On /dev/disk1, can you remove GPT #4,5,6,7,8 and create a single FAT partition which it can divide as it pleases?

The installer is refusing to use partitions which have partial installs (the No Name EFI) stuff.

I would highly recommend downloading GPT fdisk from SourceForge.

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Answer 10

Aug 12, 2014 2:14 PM in response to Loner T

Hi,

I just did the following to restore the partition layout of my 1TB Fusion Drive (all data will be erased - use Time Machine to backup and restore), maybe there is an other way, but it worked for me:

1. create a Time Machine Backup of all your Data

2. boot into Recovery with CMD+R at Mac startup

3. identify the ID of your coreStorage (connection between HDD and SSD = Fusion Drive)

diskutil coreStorage list

|

+-- Logical Volume Group XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX

4. use the Terminal to delete the coreStorage with the command

diskutil coreStorage delete XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX

5. run the Disk Utility (GUI) from Recovery Mode - HDD and SSD partitions are red now - click on one of them - the tool asks, if you want to restore the Fusion Drive - ALL your data and partitions will be erased if you proceed

6. restore your OS X with the Time Machine Backup

That's it, now I'll try Bootcamp again...

Chris

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Answer 11

Dec 15, 2015 1:59 PM in response to supersonic_jet

Dood, you are AWESOME. Thank you for the save. You were the first tutorial that had us deleting the coreStorage which had held things up prior and produced all kinds of "failed to unmount" messages. Thank you.

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