@Samir , did you register yours to get the expiration date?
My drives would show as "NaN-undefined-NaN" on the "Expiration Date". Trying the product registration failed with error " Sorry! Product registration failed, please try later (STATCODE103) "
Adding my experience - I've bought quite a lot of storage in my day and was well aware, given the price, that this 18TB Ultrastar was a possible roll of the dice in terms of WD honoring the warranty. However, I have done a lot of business with OWC in the past and have had good experiences with their support so I went for it. Worst case, OWC would honor the warranty, right? And unlike random sellers that come and go on ebay, newegg, amazon... OWC was likely to still be around when the time came for a replacement.
When I got the drive, the serial revealed no WD coverage, despite the description declaring so on the OWC website. So I got in touch with OWC to confirm they would cover the warranty and they told me that OWC will only cover their standard 90 day warranty and for the long term warranty I need to go back to WD, which I then did. WD were adamant that they would not cover the warranty and I need to take it up with the retailer. So I did...
<insert standard tedious support loop nightmare between multiple companies here>.
It resolved by me being very pushy with WD, them escalating the support, me waiting 10+ days, bugging them every few days to please update the status of my support ticket, and finally WD responding saying they would honor the 5 year warranty.
My takeaway: Unless you don't care about the warranty (or the time-suck of dealing with support), it's not worth the headache of rolling the dice with these drives on OWC, despite the great price. I have bought 10+ EXOS drives from Amazon.com, sticking with sellers I have had good experiences with, and I will go back to that method for future purchases. For my part of the world, Amazon is easier to do returns with as well, should you end up with a non-covered drive and need to make a return.
Hope this helps someone make the choice that works for them.