I recently replaced an older WD drive . All went well and there are no
problems..but I am trying to analyze what went wrong with the old drive.


The machine had been occasionally locking up and the WD quick test
failed with error code 0003


I could find no listing of that code on WD's site

I did find a 103 code that said "write fault error"



Interestingly, the drive passed the long test.
Possibly the long test just checked the disk's surface.