The media is likely to be defective.
11.9 GByte OK (25081857 sectors)
50.5 GByte DATA LOST (105955327 sectors)
Details: 0 KByte overwritten (0 sectors)
0 KByte slightly changed (< 8 bit/sector, 0 sectors)
50.5 GByte corrupted (105955327 sectors)
0 KByte aliased memory (0 sectors)
First error at offset: 0x00000002f38f9000
Expected: 0x00000002f38f9000
Found: 0x0000000000000000
H2testw version 1.3
Writing speed: 10.8 MByte/s
Reading speed: 10.0 MByte/s
H2testw v1.4