H2testw results:

The media is likely to be defective.
7.4 GByte OK (15691241 sectors)
23.8 GByte DATA LOST (49914391 sectors)
Details:0 KByte overwritten (0 sectors)
0 KByte slightly changed (< 8 bit/sector, 0 sectors)
23.8 GByte corrupted (49914391 sectors)
0 KByte aliased memory (0 sectors)
First error at offset: 0x00000001dedbd200
Expected: 0x00000001dedbd200
Found: 0xc040763ac0f094a0
H2testw version 1.4