My WD 5TB external HDD (WD50NDZW-11A8JS) is showing a Caution status in CrystalDiskInfo. The SMART values are C5 = 2, 05 = 0, C6 = 0, C7 = 0, and C4 = 0, with only 216 power-on hours. I bought the drive in October 2021 and usually keep it disconnected. The warning appeared after I transferred roughly 445 GB of data to it. The transfer completed, although it was slightly slower than usual, and I can still open videos from the drive normally. After several more hours of use, the C5 value remains at 2 and no other values have changed. This is currently the only copy of my data, so I would prefer to arrange a backup before running a full surface test. Is this possibly a temporary issue, or should I already consider the drive unreliable? Would it be reasonable to keep using it for now while monitoring C5, 05, and C6, or is replacement the safer choice? New 5TB external drives are currently very expensive where I live, so I would rather avoid replacing it unless necessary.
2 Answers
The safest practical advice is to replace it after securing a backup. Low usage does not guarantee that a hard drive will remain healthy; defects can appear because of manufacturing variation, aging while stored, handling, or a sector becoming marginal when it is finally read. The fact that the data is currently accessible does not prove the drive is dependable, so use it only for nonessential copies until you can replace it.
C5 represents sectors that the drive has marked as unstable or pending further testing. They may eventually be remapped to spare sectors, but there is no reliable way to know how many spare sectors remain or whether the drive will develop more problems. Since the value is already nonzero, treat the drive as unreliable: back up the data as soon as possible, avoid storing anything important on it, and watch whether C5 or other error counts increase. If it were still under warranty, replacement would be the straightforward choice.
It is out of warranty, so I may need to budget for a replacement. Is it possible for a drive to develop this kind of problem despite having very little power-on time? It was stored disconnected and kept in a protective pouch most of the time.