hey that's amazing. 0 kb disk is gone now! thank you!
what's the next step!
here is result of diskutil command
Mihais-iMac:~ mihaibica$ 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 disk2 1000.0 GB disk0s2
/dev/disk1 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *28.0 GB disk1
1: EFI EFI 314.6 MB disk1s1
2: Apple_APFS Container disk2 27.7 GB disk1s2
/dev/disk2 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +1.0 TB disk2
Physical Stores disk1s2, disk0s2
1: APFS Volume Macintosh HD 11.0 GB disk2s1
2: APFS Volume Preboot 82.3 MB disk2s2
3: APFS Volume Recovery 525.0 MB disk2s3
4: APFS Volume VM 2.1 GB disk2s4
5: APFS Volume Macintosh HD - Data 501.1 GB disk2s5
/dev/disk3 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *4.0 TB disk3
1: EFI EFI 209.7 MB disk3s1
2: Apple_HFS MTB HardDrive 4.0 TB disk3s2