Reset SMART Error #5?

A SMART error in the Re-allocated Sector Count attribute is very serious. It means that the drive has developed an excessive number of bad sectors, so you should not trust it with your data. I’m not aware of any freeware that is able to clear the SMART data, but I know that WD has an internal (proprietary) factory utility called Trex that can recertify your drive, possibly with one less head. There are also commercial data recovery software that can do this, but these cost more than a new drive.