What causes Offline_Uncorrectable sectors?

• A. Severe media damage or unreadable blocks
• B. Software corruption
• C. Normal wear-and-tear
• D. Low-power mode

Answer: (A)

Offline_Uncorrectable sectors occur when the drive encounters blocks that cannot be recovered by its error‑correction mechanisms during an offline read/verify. This usually points to physical damage on the media or unreadable blocks that the firmware cannot fix, so the data can’t be restored and the sector is flagged as uncorrectable. That’s why severe damage to the disk media or blocks that are unreadable is the explanation that fits best. Software corruption, normal wear, and low-power mode don’t directly produce uncorrectable hardware sectors—the issue is tied to the physical integrity of the media and the drive’s ability to read and correct those bits.