Windows 8.1 installer wont format my partition (NTFS/MBR-GUID problems) SOLVED

[Barrylight]

Hello
I think i've tried all, read this post :
https://www.tonymacx86.com/threads/windows-10-yosemite-dual-boot-same-hdd.173674/

But i'm still stuck:
I did my USB stick for uefi systems, but can't get the windows intaller to format my disk, I'm installing it on a partition of a data Disk in my hackintosh so basically :
HDD system Sierra (unplugged when i try)
HDD DATA - one 1,75To partition in Mac extended (empty)
- one 0,25To partition in mac extended, that i supposed to format whith the windows Installer. But says grey.

When I try to format my partition in NTFS before (using paragon), the windows installer says its MBR and not GUID, and clicking format don't work.
I run out of ideas... HEEELPPP thanks a lot
barry

 

[Going Bald]

Do not format the Windows-to-be partition MBR with Sierra Disk Utility. Format it Mac GPT+, then delete it with the Windows installer and install Windows in the free space. See the pinned guides at the top of this forum.

 

[Barrylight]

Yeeeey
Okay I didn't get the part when you have to delete the HD before using it in the installer.
Okay works perfect now, My machine Runs Serra & Windows 8.1. PER-FEC-TLY. I'm very happy, and will go eat something after two days