Seatools is a tool that can be used to test and diagnose internal and external harddisks manufactured by Seagate. It can be installed and used on Windows. There does not appear to be a Linux version available.
Seatools can be downloaded from here and installed easily on Windows.
Connect the harddisk you want to diagnose and then run Seatools. If you cannot find it in the Start menu, just check
C:\Program Files (x86)\Seagate\Seatools for Windows for an executable to run.
When it starts it takes a lot of time looking for ATA, SCSI and USB drives connected to your computer.
After it starts, it shows the drives it has detected. For my external USB drive, it showed up both as the external USB drive and as an internal drive. I guess this external drive was actually created from an older internal drive series or something like that.
Select the drive and choose from the above menu to get its information or run short tests. My drive failed in the short test itself.
If the drive fails any test, it is probably unrepairable and needs to be returned (if under warranty) for a replacement or just discarded. Seatools allows you to enter the Serial and Product numbers and checks if the drive is in warranty for you.
From the Seagate website you can create a return order which Seagate calls RMA and then return the device using the order and labels it provides.
Tried with: Seagate Backup Plus Portable Drive 1TB