How To Install Windows on Another Disk Manually (BIOS/MBR)

Installing Windows manually on a separate disk under BIOS/MBR can be useful for legacy systems or client setups. This guide provides a step‑by‑step process using DISM, ensuring proper partitioning and recovery configuration.

Connect & Download

Connect the target disk (HDD/SSD) to your computer.
Download the Windows ISO file from Microsoft’s official website, or use a custom image (.wim or .esd).

Mount the ISO

Right‑click the ISO and select Mount.
Note the drive letter (e.g., G:). Inside, locate sources\install.wim or install.esd.

Prepare the Target Disk (MBR Layout)

diskpart
list disk
select disk 1   (replace 1 with target disk number)
clean
convert mbr

Create Required Partitions

System Reserved Partition

create partition primary size=500
format fs=ntfs quick label="System"
assign letter=S
active

Windows Partition

create partition primary
format fs=ntfs quick label="Windows"
assign letter=V

Recovery Partition

shrink desired=1026
create partition primary
format fs=ntfs quick label="Recovery"
set id=27
assign letter=R

Apply Windows Image

dism /get-wiminfo /wimfile:G:\sources\install.wim
dism /apply-image /imagefile:G:\sources\install.wim /index:1 /applydir:V:\

Replace drive letters and file names as appropriate.

Install Boot Files

bcdboot V:\Windows /s S: /f BIOS

Configure Recovery Partition

reagentc /disable
mkdir R:\Recovery\WindowsRE
del /f /q V:\Windows\System32\Recovery\ReAgent.xml
xcopy /h /y /r V:\Windows\System32\Recovery\Winre.wim R:\Recovery\WindowsRE\
V:\Windows\System32\reagentc /setreimage /path R:\Recovery\WindowsRE /target V:\Windows
reagentc /enable

Finalize Setup

diskpart
list volume
select volume R
remove letter R
select volume S
remove letter S
exit

Boot from the New Drive

If using the same PC: set the new disk as the first boot device in BIOS/UEFI, with Legacy BIOS mode enabled.
If sending to a client: they simply connect the drive and boot.

On first boot, Windows will continue with OOBE (Out‑of‑Box Experience) for region, keyboard, and account setup.

Verify Recovery

reagentc /info

Confirm WinRE is enabled. If disabled, run reagentc /enable.

This manual installation ensures a properly partitioned MBR disk with a dedicated recovery environment, mirroring official Windows Setup behavior.

By following these steps, you gain full control over the installation process and ensure a reliable, professional Windows deployment.