Bootcamp partition failure on 27" 5K iMac

I've seen similar questions here on the forums, but not what I have been looking for. I have a 27" 5K iMac with 2TB Fusion drive. I've always did the Bootcamp thing on all of my previous machines with no hitch. The problem I'm running into is when running the Boot Camp Assistant (since I didn't feel like fudging around with Apple's funky Fusion system) but it downloads the support software and then tells me it couldn't partition the drive and to run Disk Utility to check for errors.

I run disk utility which shows everything if "OK". I check both the actual fusion volume as well as the entire drive. No issues. I try again and the same problem. Then I reboot into recovery mode and run disk utility...same outcome. Reboot and still won't partition!!!😠

Now I'm frustrated so I open Disk utility and try to just do a plain ol partition. Nope. Telling me something is wrong with disk and cannot again.

1. All USB items including my RAID drive are unplugged.
2. The machine was just purchased recently (<3 mths)
3. Nothing big has been done to this machine yet.

So pretty much a pristine from Apple 5K iMac that can't partition and install my Windows 10 iso. 😠

Any quick fix?

Thanks