You cannot use standard Windows installation prompts. You must manually partition your target storage drive using diskpart on your host PC. Open Command Prompt as Administrator and type diskpart . Type list disk to find your SD card or USB drive. Clean the disk and convert it to GPT.
Since you clearly want to run a full Windows OS on ARM64 hardware, follow this legitimate workflow instead of chasing the Windows 8.1 ghost. windows 81 arm64 iso install
When Windows 8.1 launched for ARM, it was branded as . It was exclusively pre-installed on specific hardware like the Surface RT and Surface 2 . You cannot use standard Windows installation prompts
Step 1 — Verify device compatibility
