WD RED warranty question

I have WD20EFRX without any documents from shop. Also haven’t any package for it. But if I check my serial on Warranty Check for End User page - its in warranty til 2016 year. Can I send RMA request in this case? HDD doesn’n recognized by OS.

Welcome to the Community.

Yes you can. However, you will need to obtain proper packing materials since this is an RMA requirement. It does not need to be the original box, but it does need to be a sturdy cardboard box filled with bubblewrap and foaming, and the hard drive needs to be sent inside an anti-ESD (Electro-Static Discharge) bag.