This is really confusing so I will put all the information I think might be useful...
I have a new HP Proliant G9 with WIndows 2012R2
I have a set of new WD Passport 2TB disks
When I plug in the WD disks they are sometimes recognised as removable (little green safely remove hardware icon) and sometimes not. I have tried different cables, different USB ports and 7 disks. I cannot get consistent results.
The disks when plugged into Windows 8.1 and Windows 7 systems are always removable.
When plugged into Windows 2012 R2 upgraded from windows 2008 R2 I would say they are more likely to be seem as removable but it is by no means certain.
I want them to be removable all the time.