"The Mystery of the Missing Bad Sectors"

WD Internal Drives Desktop & Mobile Drives
1

WD40EFRX - 4Tb Red

Drive Stopped being recognised in OS
DLGDIAG shows SMART Pass but Extended test shows "Too many bad sectors detected”
Use ddrescue to backup data, shows many read errors and bad blocks (but most data seems recovered)
Start RMA process
Zero-fill the drive to wipe personal data
DLGDIAG extended test now passes

Surely the bad sectors are still bad? Should I continue with the RMA? I don’t have much faith in the drive now. Can someone please advise me on the best course of action?

Thanks!

2

My understanding is that bad sectors are relocated. There’s reserved space on the disk for that purpose. Once the sector is relocated, the bad sector is mapped to the good sector. So another scan will no longer see the bad sector.