Thank you for the response. I realize that this system is beyond help, both yours and in general. To answer your question, the RAID5 was set to GPT. Conclusion: after a full 8 hrs. of trying different ideas I finally determined that this mobo just will not support EFI installation of a Microsoft Server OS newer than 2008 (not R2). We opted to migrate the installation to the S2600CP2 with much better results. As an aside, One of the problems with Server 2012 R2 being loaded in EFI is that you cannot run Windows Server back up to get a full image of the system because the default size of the recovery partition (300MB) is about 20-40MB too small to allow VSS to run. You have two options, create a 50 - 100MB partition at the front of the drive(array) at the time of OS install and then use Gparted to expand the Recovery partition into that extra space which I have had great success on SuperMicro X10 series systems with. Unfortunately it does not seem to work on the S2600CP2. So, I was left with option two. I was forced to use the repair CLI in Advanced options on the install media and Diskpart to create the required partitions (EFI, Recovery and system), manually copy the Winre.wim file to the recovery partition (hint you need xcopy /h) then manually load the OS from the optical media from the CLI. This is by no means a fault of yours, but thought I would share for your own KB.
Regards,
Ken Mc