WD Book Duo -Red Plus 14TB Extended SMART Test stuck at 90%

[nf24eg]

Hello, I have WD My Book Duo, inside it 2 * WD Red Plus 14TB

SMART says:

Extended self-test: in progress
10% remaining
Recommended time: 1389 minutes (~23 hours)

The test has been running for 3+ days and is still at 10% remaining.

SMART shows:

Reallocated_Sector_Ct 0
Current_Pending_Sector 0
Offline_Uncorrectable 0
Reallocated_Event_Count 0
No Errors Logged
Pending Defects No Defects Logged

Is it normal for the test to stay at 90% for this long when the drive is connected through the My Book Duo (testing it one by one, not 2 hdds inside).

Also the WD utilities gives the same result, everything is ok but the extended test takes +3 days at 90%

Thanks.

[DataWizard0103]

The SMART numbers look healthy, so the part that stands out is the My Book Duo USB enclosure. A long SMART extended test can become extremely slow when the drive is being tested through a USB bridge rather than directly through SATA, especially near the end when the drive is doing its final surface checks. I would not treat “90% for 3 days” by itself as a failed drive when there are no pending, reallocated, or uncorrectable sectors. The useful test is to connect each WD Red Plus directly to a SATA port if possible and run the extended test there. If it completes normally, the enclosure or its USB bridge is the likely reason for the misleadingly long test. Also make sure the PC is not sleeping or powering down the drive during the test.