Voici le rapport diskutil list de tous les disques connectés (celui qui pose problème est le disk3).
diskutil list
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *251.0 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_CoreStorage Macintosh HD 250.1 GB disk0s2
3: Apple_Boot Recovery HD 650.0 MB disk0s3
/dev/disk1 (internal, virtual):
#: TYPE NAME SIZE IDENTIFIER
0: Apple_HFS Macintosh HD +249.8 GB disk1
Logical Volume on disk0s2
14527C63-E550-44F5-AD0E-A08CDB7D5262
Unencrypted
/dev/disk2 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: FDisk_partition_scheme *160.0 GB disk2
1: Linux 19.8 GB disk2s1
2: Windows_NTFS STOREVA MINI NTFS 140.3 GB disk2s2
/dev/disk3 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *480.1 GB disk3
1: EFI EFI 209.7 MB disk3s1
2: Apple_HFS Crucial M500 - A 239.5 GB disk3s2
3: Apple_Boot Recovery HD 650.0 MB disk3s3
4: Apple_HFS CrucialM500 239.6 GB disk3s4