1. I safely removed the disk before pulling the USB cable
2. Other files copied on the maxtor disk are fine.
3. I have yet to correct my source C drive, since my download is not complete yet.
4. I will disable write caching, that seems to have cause corruption in my source file system. (internal), usually my PC is ON and monitor is off, my folks at home will just come and try to power on which will kind of shutdown the machine.
5. The copy on another usb hdd works fine, and this is the issue only with this HDD.
6. I am going to run chkdsk as well on external disk and then will post the results.
thanks.