Windows 10: Possible to sysprep on UEFI box, then install HDD in Legacy BIOS box?

@darthfoolish, this is both extremely easy and completely OK to do without activating Windows 10 on the HDD you will send to your father-in-law. In fact, it's important that you forget this nonsense about it being against EULA; for the first, it isn't. You'll do this in an hour or two, well covered by the grace period you are allowed to use Windows before activating it, and for the second, in this case it would be plain stupid to activate Windows just to install it, then lose the activation when HDD is plugged in on another PC.

Personally I will never use a product key and activate my reference machines, physical or VM, when I know that I will only use Windows on it for an hour or so, to create a deployment image.

Simple instructions. Really, don't panic because of length of this post, this is simple. See screenshots of each step at the end of this post:

1.) Connect the HDD going to your father-in-law as secondary HDD on your PC, boot to your own Windows 10.

2.) Open an elevated Command Prompt, start Windows Disk Partitiononing Utility with following command:

diskpart

3.) Check the disk number of that HDD going to your father-in-law and select it with following two commands

list disk

sel disk 2

In this example case now, the selected HDD in question is Disk 2

4.) Clean the disk:

clean

5.) Convert it to MBR:

convert MBR

6.) Create 500 MB System Reserved partition:

create part primary size=500

7.) Format and label it:

format quick fs=ntfs label="System"

8.) Assign a temporary drive letter for it:

assign letter="S"

9.) ... and mark this System reserved partition as active:

active

10.) Create Windows partition using rest of the disk:

create part primary

11.) Format and label Windows partition:

format quick fs=ntfs label="Windows 10"

12.) Assign a temporary drive letter for Windows partition:

assign letter="Z"

13.) Exit DISKPART:

exit

14.) Mount a Windows 10 ISO, in my case now it got drive letter J:. Check which Windows editions it contains to find out index number for edition you want to install to your father-in-law:

dism /Get-WimInfo /WimFile:J:\Sources\install.wim

In my case now I decided to install Pro edition, index #8.

15.) Install (deploy) selected edition to partition created in steps 10 through 12 above:

dism /Apply-Image /ImageFile:J:\Sources\install.wim /Index:8 /ApplyDir:Z:\

16.) Add newly deployed Windows to your PC's boot menu:

bcdboot Z:\Windows

17.) Windows on partition Z: is now default OS, the one booted to if user makes no selection from boot menu in given time, default 30 seconds. Let it be default for now, just rename the boot menu entry to better recognize correct entry. In my case now I renamed it to W10MBR:

bcdedit /set {default} description "W10MBR"

18.) Restart your PC, booting to W10MBR. When it arrives to Region Selection screen at the beginning of OOBE (Windows Welcome), reboot to Audit Mode:



19.) Follow instructions in this tutorial to customize your father-in-law's Windows10: Create media for automated unattended install of Windows 10 Windows 10 Tutorials

In your case you can forget steps Three, Six and Eight in above mentioned tutorial, only doing the highlighted ones. In Step Seven you only need to do 7.1 through 7.6 and then 7.9 (screenshot from tutorial):



In fact, if no customizations are required you can forget everything else in that tutorial except Step 7.9, the Sysprep.

20.) When done and PC has shut down after Sysprep, dismount the HDD and send it to your father-in-law. Depending on level of customizations you choose to do, this whole process takes anything from half an hour to two hours.

Your father-in-law naturally needs a valid license / product key to activate Windows 10 when this HDD is booted on his PC and he starts to use Windows.

Screenshot to cover steps 1. through 13.:



Screenshot, step 14. (checking edition index):



Screenshot for steps 15. through 17.:




That's it.

Kari

Kari said:

@darthfoolish, this is both extremely easy and completely OK to do without activating Windows 10 on the HDD you will send to your father-in-law. In fact, it's important that you forget this nonsense about it being @ EULA; for the first, it isn't. You'll do this in an hour or two, well covered by the grace period you are allowed to use Windows before activating it, and for the second, in this case it would be plain stupid to activate Windows just to install it, then lose the activation when HDD is plugged in on another PC.

Personally I will never use a product key and activate my reference machines, physical or VM, when I know that I will only use Windows on it for an hour or so, to create a deployment image.
Kari

I agree - it is insane to expect users to activate everything especially VMs for just a one-off task.

We obviously should as a responsible forum not actively encourage usrs to run unactivated versions on a permanent basis.

However, for cases like this where it is clear the end result will be a totally legitimate permanent installation, I do not see why we should get so uptight about it - common sense should prevail

I suggested vms but your way of dual booting the hdd is equally as good as it does not impact existing installation.

Just one minor addition to your instructions - when OP has finished the job, OP should remove the dual boot entry using msconfig.