I run the Datalifeguard diagnostic tool on a My Book Essential 1110 1TB external drive. The result is:
Test Option: QUICK TEST Model Number: WD My Book 1110 Unit Serial Number: [Deleted]
Firmware Number: 2018 Capacity: 999.50 GB SMART Status: PASS Test Result: FAIL Test Error Code: 06-Quick Test on drive 2 did not complete! Status code = 07 (Failed read test element), Failure Checkpoint = 105 (Unknown Test) SMART self-test did not complete on drive 2! Test Time: 17:31:28, November 01, 2012
Test Option: EXTENDED TEST Model Number: WD My Book 1110 Unit Serial Number: [Deleted]
Firmware Number: 2018 Capacity: 999.50 GB SMART Status: PASS Test Result: FAIL Test Error Code: 08-Too many bad sectors detected. Test Time: 17:48:43, November 01, 2012
I'd opened a case in the WD support page, but no feedback after 10 days.