This is my advice:
Take a Windows machine and clean your drives with the following commands.
----Windows (7,8,8.1,10,server)----
Open (Administrator) Command (CMD)
Type : diskpart
Type : list disk
Type : select disk (xx) (Where xx is your number of 'wanted' harddrive for your Synoboot Rig without the ( ) ).
Type clean all
!!!
Wait for an 15 minutes or so, depending on your size and capacity.
You can select the command 'clean', but this is not so thorough as 'clean all', but it is faster.
!!!
In the meanwhile create your "usb stick" with synoboot that I provide as an attachement.
I REMIND YOU > THIS IS BASED ON AMD's BAREMETAL RIG's!
Create USB-stick > USB Stick (AMD)(Alt)
I already enhanced/alternated the VID > PID with this image and should work
on almost any AMD > Baremetal Rig with SATA300 > 600. If you are familiar with Linux you can install your SATA Controller drivers, but then again,
feel free to test it yourself!
Right, after Diskpart stated that your drives where cleaned succesfully go to the next step!
Plug your USB Stick in to your AMD (Synoboot RIG) machine.
Plug your SATA Harddrives in to your AMD (Synoboot RIG) machine.
Boot up
Now wait for 1 or 2 minutes and then go to the following website: http://find.synology.com
Now run the wizard with the latest (at these times) DSM 6.0.2 PAT file found on the http://synology.comwebsite
I REMIND YOU Once more : 12-BAY > DS3615XS.
If it asking to install the latest DSM version, just do it manually, in the future this won't work with the provided image!(My image: USB Stick (AMD))
Do not ENABLE AUTOMATIC UPDATES.
It should work just fine from here!
Happy NASsing!
https://mega.nz/#!q0pz1IgQ