ntfsfix /dev/sdb1
Mounting volume... ntfs_mst_post_read_fixup_warn: magic: 0x00000000  size: 1024   usa_ofs: 0  usa_count: 65535: Invalid argument
Record 0 has no FILE magic (0x0)
Failed to load $MFT: Input/output error
FAILED
Attempting to correct errors... ntfs_mst_post_read_fixup_warn: magic: 0x00000000  size: 1024   usa_ofs: 0  usa_count: 65535: Invalid argument
Record 0 has no FILE magic (0x0)
Failed to load $MFT: Input/output error
FAILED
Failed to startup volume: Input/output error
Checking for self-located MFT segment... ntfs_mst_post_read_fixup_warn: magic: 0x00000000  size: 1024   usa_ofs: 0  usa_count: 65535: Invalid argument
OK
ntfs_mst_post_read_fixup_warn: magic: 0x00000000  size: 1024   usa_ofs: 0  usa_count: 65535: Invalid argument
Record 0 has no FILE magic (0x0)
Failed to load $MFT: Input/output error
Volume is corrupt. You should run chkdsk.

partx -l /dev/sdb1
# 1:        63-625137344 (625137282 sectors, 320070 MB)

partx -s /dev/sdb1
NR START       END   SECTORS   SIZE NAME UUID
 1    63 625137344 625137282 298.1G