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Damaged Fusion Drive is missing a disk - Can I Rebuild the MBR?

speedjohnson

speedjohnson

macrumors newbie
Original poster
Hey there,

Long time lurker so first wanna say thanks for all the help over the years.

(Edit - it seems I need to somehow repair the permission table)

Here's my trouble:

Today I tried to reinstall Windows using bootcamp on my 1TB fusion drive.

I was getting the error message that windows could not be installed because " The selected disk has an MBR partition table. On EFI systems, Windows can only be installed on GPT disks. "

After trying some different suggestions I tried this one:


Which showed me how to convert the MBR to a GPT using MS DOS during the windows installation.

Oh dear.

My Mac now no longer recognises the fusion drive (circle with line through it) and I get this message in disk utility:











I'd be happy to format and start again but stupidly didn't back up my Mac hard drive before fiddling around, would like to know if there is anyway of rebuilding the MBR / fixing the fusion drive without formatting?


THere's this cool little program http://www.partitionwizard.com/help/rebuild-mbr.html but not sure if there's a way to open during the windows installation - it obviously wont open with the mac.

Any help would be much appreciated!

Cheers in advance 😉
Adam


iMac (Retina 5K, 27-inch, Late 2014), Mac OS X (10.7.5), null
 
Last edited:
Edit:


It seems I need to repair the partition table, but can't seem to find how to do this...



Also it seems the two partions within the overall Fusion drive are ok - its the "overall" Internal Drive that is show "Offline"



-bash-3.2# diskutil corestorage list

CoreStorage logical volume groups (1 found)

|

+-- Logical Volume Group AC79ACAF-A36B-4F07-BB9A-9CF92DF796BD

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

Name: Internal Drive

Status: Offline

Size: 862577819648 B (862.6 GB)

Free Space: -none-

|

+-< Physical Volume 909F3B47-0438-40C3-9DF2-C970AF02FE75

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

| (No properties)

|

+-< Physical Volume 350EB3CD-6DBD-4D9D-9A27-DD611299AF24

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

Index: 1

Disk: disk1s2

Status: Checking

Size: 862577819648 B (862.6 GB)

-bash-3.2# sudo diskutil list

-bash: sudo: command not found

-bash-3.2# diskutil list

/dev/disk0

#: TYPE NAME SIZE IDENTIFIER

0: *121.3 GB disk0

/dev/disk1

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_CoreStorage 862.6 GB disk1s2

3: Apple_Boot Boot OS X 134.2 MB disk1s3

4: Microsoft Basic Data 130.0 GB disk1s4

5: Apple_HFS Untitled 7.0 GB disk1s5

/dev/disk2

#: TYPE NAME SIZE IDENTIFIER

0: Apple_partition_scheme *1.3 GB disk2

1: Apple_partition_map 30.7 KB disk2s1

2: Apple_HFS OS X Base System 1.3 GB disk2s2

/dev/disk3

#: TYPE NAME SIZE IDENTIFIER

0: FDisk_partition_scheme *32.1 GB disk3

1: Windows_FAT_32 CANON 32.1 GB disk3s1

/dev/disk4

#: TYPE NAME SIZE IDENTIFIER

0: untitled *5.2 MB disk4

/dev/disk5

#: TYPE NAME SIZE IDENTIFIER

0: untitled *524.3 KB disk5

/dev/disk6

#: TYPE NAME SIZE IDENTIFIER

0: untitled *524.3 KB disk6

/dev/disk7

#: TYPE NAME SIZE IDENTIFIER

0: untitled *524.3 KB disk7

/dev/disk8

#: TYPE NAME SIZE IDENTIFIER

0: untitled *524.3 KB disk8

/dev/disk9

#: TYPE NAME SIZE IDENTIFIER

0: untitled *524.3 KB disk9

/dev/disk10

#: TYPE NAME SIZE IDENTIFIER

0: untitled *6.3 MB disk10

/dev/disk11

#: TYPE NAME SIZE IDENTIFIER

0: untitled *2.1 MB disk11

/dev/disk12

#: TYPE NAME SIZE IDENTIFIER

0: untitled *1.0 MB disk12

/dev/disk13

#: TYPE NAME SIZE IDENTIFIER

0: untitled *524.3 KB disk13

/dev/disk14

#: TYPE NAME SIZE IDENTIFIER

0: untitled *524.3 KB disk14

/dev/disk15

#: TYPE NAME SIZE IDENTIFIER

0: untitled *1.0 MB disk15

/dev/disk16

#: TYPE NAME SIZE IDENTIFIER

0: untitled *6.3 MB disk16

/dev/disk17

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *3.0 TB disk17

1: EFI EFI 209.7 MB disk17s1

2: Apple_HFS M' Drive VI 3.0 TB disk17s2

-bash-3.2#









Any ideas?
 
Thanks for the tip,

I tried that late last night but seems I'm having problems making a bootable drive on the mac - tried using Unetbootin but says "this will not boot from a mac, use a PC",

Do you have any tips on how to mac a GParted bootable USB on the Mac - all the advice and alternative programs I can find seem to be PC based.

Thanks for your help 🙂
 
Sorry to say, but I think you are out of luck here. Your windows/dos boot partition conversion destroyed the block level based fusion drive organization. There is not much information available about the underlying principles of a fusion drive and I know of no repair program to do so.

Take it for lessons and never ever do NOT backup a dual drive setup, where the failure rate doubles compared to a single drive system. Or basically: Without one backup at least consider any drive lost already.
 
Last edited:
No worries, thanks for your reply - it does look fairly impossible doesn't it.

Rather than restoring a working drive - do you think there would be any hope for scanning for lost files after the format? Or is do you think this carnage will have caused too much damage?
 
I used DiskDrill in the end, managed to rescue most of it in the end (DiskWarrior didn't recognise it at all)

This is a great video for rebuilding a Fusion drive once you're ready to reformat and wipe the slate clean:

 
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