Have a read of post two.

Drive would need to be all unallocated, for Windows 10 to make the System Recovery partition.

I would use a VM.
...

DISABLE Quick Boot in the BIOS.

Hi

My Windows to Go installed in 30 mins.

This is the other one.



Download Windows Technical Preview ISO - Microsoft Windows

TechNet Evaluation Center



Windows 10 Technical Preview for Enterprise | TechNet Evaluation Center

Do you have your dual boot menu now ?
https://www.tenforums.com/installation-and-setup/2044-boot-select-screen.html

If NO, run EasyBCD first, than remove drive letter.

Try using EasyBCD 2.2 in Win 8 to add Windows 10 to boot.
EasyBCD - NeoSmart Technologies

The same as doing Windows 7 & 8.
Dual Boot Installation - Windows 8 and Windows 7 or Vista

Windows 8.1 had problems with NVIDIA Geforce cards.

Windows 10: Why Microsoft skipped Windows 9 - Gadgets and Tech - Life and Style - The Independent

This is not a VM.

No Upgrade problems, Windows 8.1 Enterprise to Windows 10 Enterprise.

5589

5590

Ray.

UEFI Bootable USB Flash Drive - Create in Windows
Have you tried Option Two.(Manually).


You could try the TechNet Evaluation Center ISO.

https://www.tenforums.com/tutorials/1950-windows-10-technical-preview-clean-install.html#step19
Step 19.

https://www.tenforums.com/installation-and-setup/1783-questions-about-dual-booting-windows-8-9-a-post149995.html#post149995

Two Updates ready.

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:ditto:

No problems with UEFI Dual boot Windows 8/8.1 & 10.

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No problems with UEFI Dual boot Windows 8/8.1 & 10. (Secure Boot ENABLED)

Disc ready & waiting.

Under £19 at dads UK...

Computer Does not Start After Installing a Video Card (Windows 8) | HP® Support

Just the OEM manufacturers wording.
My wording in most posts is UEFI/BIOS frimware.

Windows 9 preview ISO file may be leaked after 15 september | Windows Blue full

Secure Boot warning screenshot.

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Secure Boot - Enable or Disable in UEFI