exFAT Hard Drive not showing up

Hello,

I have an internal HD (using the data doubler) that i formatted as exFAT. The problem is that after formatting the HD, followed by a restart of my macbook, it no longer shows up under "Devices" on the finder sidebar, and when i go to disk utility it shows that the HD "Not Mounted" .. the name even changed from what i originally set it to, from "Example Disk" to "disk1s2" ?

I want to use this HD for windows bootcamp and Mac. Finally, I went into the Windows side to see if it showed up and it didn't show up there either.

i tried formatting twice already and both times i'm experiencing this problem.

What can i do so that the disk will properly show up each time i fire up the computer ? When the HD was formatted as Mas OS Extended (Journaled) it would show up on both windows and mac, but windows coulnt read the files.

thanks in advance,

kind regards.