If your external drive is one of the "slim" types I would replace it with one that uses the kind of 5.25 inch drive mechanism that is used in desktop computers. Such as this OWC Mercury Pro, for $69.75. Or, alternatively, you could purchase an Asus bare drive or other high quality 5.25 inch bare drive from Newegg.com for less than $20, and put it in an inexpensive external drive enclosure that provides a SATA internal interface and a USB external interface. Many such enclosures are available at Newegg.
The reason I make that suggestion is that I’ve found that various slim external drives, and also optical drives that are built into laptops, often have problems reading discs that are in less than perfect condition. While those same discs will be read by inexpensive 5.25 inch drives with no problem.
I also concur with the others that the software that is chosen should assure bit perfect copying.
Regards,
-- Al
The reason I make that suggestion is that I’ve found that various slim external drives, and also optical drives that are built into laptops, often have problems reading discs that are in less than perfect condition. While those same discs will be read by inexpensive 5.25 inch drives with no problem.
I also concur with the others that the software that is chosen should assure bit perfect copying.
Regards,
-- Al