Non, c'est la nouvelle structure du format APFS dans un disque dur. D'un côté il y a Macintosh HD qui contiendra macOS Catalina (les fichiers système) et qui sera quasiment intouchable, de l'autre coté Macintosh Données contenant les données de l'utilisateur. Pour le moment ce n'est pas facile à comprendre, mais c'est une sécurité supplémentaire pour protéger macOS de son utilisateur.Ce serait donc bien Catalina qui m'aurait foutu le bazar. Merci pour l'info. rapide je teste et je rends compte.
sw_vers -productVersiondiskutil list-bash-3.2# 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_APFS Container disk3         1000.0 GB  disk0s2
/dev/disk1 (internal):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                         28.0 GB    disk1
   1:                        EFI EFI                     314.6 MB   disk1s1
   2:                 Apple_APFS Container disk3         27.7 GB    disk1s2
/dev/disk2 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        +2.1 GB     disk2
   1:                  Apple_HFS OS X Base System        2.0 GB     disk2s1
/dev/disk3 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +1.0 TB     disk3
                                 Physical Stores disk1s2, disk0s2
   1:                APFS Volume Macintosh HD - Données  20.5 KB    disk3s1
   2:                APFS Volume Preboot                 28.7 KB    disk3s2
   3:                APFS Volume Recovery                20.5 KB    disk3s3
   4:                APFS Volume VM                      3.2 GB     disk3s4
   5:                APFS Volume Macintosh HD            20.5 KB    disk3s5
/dev/disk4 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +5.2 MB     disk4
/dev/disk5 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk5
/dev/disk6 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk6
/dev/disk7 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk7
/dev/disk8 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +2.1 MB     disk8
/dev/disk9 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk9
/dev/disk10 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk10
/dev/disk11 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +12.6 MB    disk11
/dev/disk12 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +4.2 MB     disk12
/dev/disk13 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +1.0 MB     disk13
/dev/disk14 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +2.1 MB     disk14
/dev/disk15 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk15
/dev/disk16 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk16
/dev/disk17 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +1.0 MB     disk17
/dev/disk18 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +6.3 MB     disk18
/dev/disk19 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +6.3 MB     disk19
/dev/disk20 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk20
/dev/disk21 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +2.1 MB     disk21
-bash-3.2#diskutil resetFusiondiskutil ap deleteContainer disk3 ; diskutil list-bash-3.2# diskutil ap deleteContainer disk3
Started APFS operation on disk3
Deleting APFS Container with all of its APFS Volumes
Unmounting Volumes
Unmounting Volume "Macintosh HD - Données" on disk3s1
Unmounting Volume "Preboot" on disk3s2
Unmounting Volume "Recovery" on disk3s3
Unmounting Volume "VM" on disk3s4
Unmounting Volume "Macintosh HD" on disk3s5
Deleting Volumes
Deleting Container
Wiping former APFS disks
Switching content types
Reformatting former APFS disks
Initialized /dev/rdisk1s2 as a 26 GB case-insensitive HFS Plus volume with a 8192k journal
Mounting disk
Initialized /dev/rdisk0s2 as a 931 GB case-insensitive HFS Plus volume with a 81920k journal
Mounting disk
2 new disks created or changed due to APFS operation
Disk from APFS operation: disk1s2
Disk from APFS operation: disk0s2
Finished APFS operation on disk3
-bash-3.2#-bash-3.2# 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_HFS Untitled 2              999.9 GB   disk0s2
/dev/disk1 (internal):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                         28.0 GB    disk1
   1:                        EFI EFI                     314.6 MB   disk1s1
   2:                  Apple_HFS Untitled                27.6 GB    disk1s2
/dev/disk2 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        +2.1 GB     disk2
   1:                  Apple_HFS OS X Base System        2.0 GB     disk2s1
/dev/disk4 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +5.2 MB     disk4
/dev/disk5 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk5
/dev/disk6 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk6
/dev/disk7 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk7
/dev/disk8 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +2.1 MB     disk8
/dev/disk9 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk9
/dev/disk10 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk10
/dev/disk11 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +12.6 MB    disk11
/dev/disk12 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +4.2 MB     disk12
/dev/disk13 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +1.0 MB     disk13
/dev/disk14 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +2.1 MB     disk14
/dev/disk15 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk15
/dev/disk16 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk16
/dev/disk17 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +1.0 MB     disk17
/dev/disk18 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +6.3 MB     disk18
/dev/disk19 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +6.3 MB     disk19
/dev/disk20 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +524.3 KB   disk20
/dev/disk21 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +2.1 MB     disk21
-bash-3.2#diskutil cs createLVG Fusion disk1s2 disk0s2-bash-3.2# diskutil cs createLVG Fusion disk1s2 disk0s2
Started CoreStorage operation
Unmounting disk1s2
Touching partition type on disk1s2
Adding disk1s2 to Logical Volume Group
Unmounting disk0s2
Touching partition type on disk0s2
Adding disk0s2 to Logical Volume Group
Creating Core Storage Logical Volume Group
Switching disk1s2 to Core Storage
Switching disk0s2 to Core Storage
Waiting for Logical Volume Group to appear
Discovered new Logical Volume Group "F76E4F97-AA15-401B-BE12-FC119B4AFF43"
Core Storage LVG UUID: F76E4F97-AA15-401B-BE12-FC119B4AFF43
Finished CoreStorage operation
-bash-3.2# 
	