Follow strictly this guide and you should be fine:
First, the disk should be gpt formatted, not msdos with MBR.
Make sure not to mix BIOS / UEFI install, both Windoze and Manjaro should be installed the same mode, i.e. in UEFI mode. To do so you have to boot the ISO USB stick in UEFI mode by selecting the entry with “UEFI” in the name when booting from your firmware.