said by donek:
Can someone tell me what is wrong with my external HD and what I can do to fix it?
Your hard disk has physical defects on the surface of its platters or some other physical (potentially mechanical) defect. You cannot repair these errors -- there have already been 345 reallocated LBAs, and there are another 1407 pending for analysis. Commonly this is referred to as a drive developing "bad sectors".
Your disk also shows definite signs of excessive ECC, indicated by extremely high counts shown in attribute 1 (the worst adjusted value seen was 053, while the trip threshold per the manufacturer is 051 -- very very close to a SMART overall health failure), which means the issue is quite extreme.
The WD20EARS (which is the model of hard disk inside of the enclosure) is a 4096-byte sector drive. So, at this point in time, you have lost 1407*4096 = 5763072 bytes (roughly 5.7MBytes) of data on the drive. You may have also lost data in the past.
Which files are impacted are unknown. A file copy from that drive should return a large number of I/O errors when reading files -- those files are, effectively, lost/damaged. They cannot be repaired by normal means (a data recovery company may be able to repair them, but no promises).
1. If the product is under warranty, RMA it. Western Digital should have absolutely no problem doing an RMA if it's under warranty -- just provide them a screenshot like you did here. If they ask for the reason verbally or via a web site, the reason is "bad sectors".
If the product is not under warranty, buy a replacement product (same brand/model, or a different brand/model -- doesn't matter), and copy as many files as you can from the bad drive (i.e. those which do not return I/O errors). For those which do: they cannot be repaired aside from relying on a data recovery company,
2. (If this data is mission critical and is very important to you / you have no backups) Contact a data recovery company. Do not attempt to run any data recovery software yourself (e.g. SpinRite and other nonsense tools), it will just make the situation worse.
Expect to pay between US$500 and US$2500 for the recovery. Good data recovery companies will give you a quote/estimate,
3. Do nothing and continue to use the product + continue to lose data.
Good luck, choose wisely, and do backups.--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.