|If you have "several" bad sectors you should not depend on that drive any longer. The condition will just continue to get worse. Before you were even aware of any bad sectors the drive had already substituted sectors from a pool of spare sectors. So you have more than you thought.|
While I have your attention, if you are using that external to save important files be sure to keep at least TWO copies of any data you need. Save them to different media. All data is subject to loss, corruption, theft, fire, etc.
Have you run Seatools on the drive? If not, I suggest you do. Get it at the link below.