Full media scan taking too long?

Hi!

I have My Passport Essential, I reformatted it to be Mac OS Extended (Journaled) and I’m doing diagnostics on WD SmartWare, performing full media scan, it has taken me so far full day, external drive is 500 GB and empty. It says that it may take hours for large drives. Afther it run first half day, it was 10% complete, then I used my computer a little and then it moved to 90% complete and has stayed 90% other half of the day. If something is wrong, will it display some kind of message or let me know what is up or if it is fine will it say that it is fine?

It’s lasting sooo long, is it supposed to be lasting so long?

…it is still scanning and shows approx 90% complete, it’s been doing it for at least 24 hours now.

Any ideas why is it taking so long?