HDClone question - Write errors

Hello...I have HDC Professional v3.7.5. I am attempting to copy a Western Digital drive (WD5000AVVS) to an identical new drive. The new drive experiences "write errors."
I have tried drive -> drive, partition -> partition, partition -> drive with various levels of write errors.
What causes "write errors" and how can I overcome this to obtain a good copy for back up purposes? Thank you...
PeterW
I have tried drive -> drive, partition -> partition, partition -> drive with various levels of write errors.
What causes "write errors" and how can I overcome this to obtain a good copy for back up purposes? Thank you...
PeterW