Local Apple support suggested me to change the 2 TB Seagate Fusion drive with a 2 TB SSD to increase speed in my 27" Retina iMac with macOS Sierra installed.

I had a full backup done with Carbon Copy Cloner in an external hard drive. Unfortunately my little son trashed the drive which was spinning and is now totally unavailable.

The original Fusion Drive, untouched after replacement, is now in an external USB3 enclosure.

While most of my important files are in Dropbox, some files are not actually lost but are in the original fusion drive.

If I connect the drive to the iMac in the USB3 port, not only it doesn't show up on the Desktop, but the Disk Utility tells me the disk is unformatted.

Is there any possible way to rescue some of the files from that drive?

I didn't do anything yet just connected it and opened Disk Utility.

I think the Drive must be partitioned in such a way so the internal 32 GB fusion no longer recognizes the old drive as the new SSD is now linked with it and no longer sees anything.

I am in deep troubles now and I wonder if using terminal or any other utility I can bring back the "Data Section" of the Fusion Drive.

The local Apple Support Centre tells me that even removing the SSD and putting back the original Seagate HD it will be impossible for the iMac to go back to the previous condition as now the 32 GB are linked to the SSD.


This is my diskutil list:

Last login: Thu Jun  7 11:14:42 on ttys000
Nuovo:~ dante$ diskutil 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            999.9 GB   disk0s2
   3:                 Apple_Boot Boot OS X               134.2 MB   disk0s3

/dev/disk1 (internal):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                         121.3 GB   disk1
   1:                        EFI EFI                     314.6 MB   disk1s1
   2:          Apple_CoreStorage Macintosh HD            120.4 GB   disk1s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk1s3

/dev/disk2 (internal, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Nuovo                  +1.1 TB     disk2
                                 Logical Volume on disk0s2, disk1s2
                                 Unencrypted Fusion Drive

/dev/disk3 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk3
   1:                        EFI EFI                     209.7 MB   disk3s1
   2:          Apple_CoreStorage Macintosh HD            2.0 TB     disk3s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk3s3

Nuovo:~ dante$
  • The fusion drive is actually the 128GB plus the spinning HDD. Once you destroy that container and create another, that data is gone. – Allan Jun 6 '18 at 18:29
  • I didnt destroy anything. The people in the shop simply removed it form the IMAC and put it as it was in an external container. In theory the Hard disk and its content should be the same as it was when I switched off the machine. whatever was there is still untouched. Is there no way to get it back? Shall i reformat and attempt rescuing what the rescue softaware might give back? Thanks – user5547053 Jun 6 '18 at 22:18
  • There are two internal drives in your iMac...a small SSD and a large HDD. The shop took out HDD and put in a large SSD. Now there are two SSDs in your iMac. Since you destroyed the container which was the original small SSD and HDD, to create a new container (small SSD and large SSD) the data is now gone. For confirmation, post the output of diskutil list to your question. – Allan Jun 6 '18 at 23:13

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