How would one create Bootable USB with Windows 10 32bit, if there are 64bit already on USB

Question

I have a Bootable USB with Windows 10 64bit (GPT parititioning) I used for my machine, which I created using Rufus.

Now I need to install Windows 10 32bit using MBR parititioning, on an older machine which is not 64bit, and I'm wondering, can I just use Rufus with new 32bit ISO image with same USB that was previously used to install 64bit version with GPT parititioning. Or I would need to format the USB first to be able to create 32bit Bootable USB properly.

Thanks in advance.

Solution

Every time you use Rufus, it formats the USB pen drive in question based on the selected input like the ISO File, Partitioning Scheme and boot type (BIOS/UEFI).

So when you select Windows 10 32 bit ISO, you can specify MBR Partition Scheme for BIOS Computer with FAT32 formatting, all previous contents of the USB Pen drive will be erased and a specified scheme shall be created on it with bootable ISO file.

See the screenshots below giving you the perspective how Rufus creates the bootable pen drive.

First it warns you that all contents of the pen drive shall be erased. So ensure that if you have any critical data on the pen drive, back it up elsewhere.

Next based on the partition scheme selected in input it will first clear previous structure and re-create desired MBR or GPT structure.

Then it will start creating the required bootable pen drive using the supplied bootable ISO file.

Additional information, though not much related. In case of UEFI Computer even if Rufus selects NTFS format and you wish to leave it as it is, there's nothing to worry. Rufus adds a small 512KB FAT partition at the end of pen drive with UEFI NTFS driver so that for UEFI with GPT partition scheme, even NTFS formatted pen drive can successfully boot just in case your BIOS Vendor has not provided NTFS Support on UEFI. First the NTFS Driver loads and then hands over the control to Windows boot loader from USB's NTFS partition.

Also note that Rufus as of now does not create Multi Boot USB Pen drive. So you can have one scheme possible at a time.

Comments

[Ramhound]

Windows 10 has used a combined ISO for both 32-bit and 64-bit for more than 2 years. However, it’s not clear, if the ISO you used was released by Microsoft or is an unofficial and/or custom ISO

[Usce]

@Ramhound It is created using media tool from Microsoft. You can still create 64 bit or 32bit depending on your choice, or create one that supports both (3 options available)

[Usce]

May I know the reason for downvote if possible?

[Canadian Luke]

@Usce Not me, but likely because of a mixup of terms and abilities. It is possible to run bootable drives in GPT/UEFI systems for 32-bit OSes, but it's uncommon; I am guessing someone downvoted for that reason

[Usce]

Maybe I've could worded my question better :) I didn't wanted to co-relate those two in such way, my main question was if it is proper to create Bootable USB with 32bit Windows and MBR parititioning on one that has already 64bit and GTP parititioning using Rufus. As answered bellow it's possible. However, thanks on pointing that out, I'll pay more attention on formulating my questions better in future :)

[Usce]

My question was, can I use the USB that already has Windows 10 on it, or should I format it first, I have USB with 64bit on it, and would like to create 32bit one on the same USB, removing the old one

[Admin]

@Usce Again, use the Media Creation Tool.

[Usce]

I've created ISO image 64bit Windows 10, used Rufus to make Bootable USB using with GPT partitioning. Everything worked well. Now I need to create 32bit Windows 10 with MBR partitioning Bootable USB. Can I use same USB now with rufus, will it be properly overwritten? Or should I format usb myself before?

[patkim]

Every time you use Rufus, it formats the USB pen drive in question based on the selected input like the ISO File, Partitioning Scheme and boot type (BIOS/UEFI). So when you select Windows 10 32 bit ISO, you can specify MBR Partition Scheme for BIOS Computer with FAT32 formatting, all previous contents of the USB Pen drive will be erased and a specified scheme shall be created on it with bootable ISO file.

[Usce]

@pat2015 thank you for answer. That is what I was interested in. Can you put that as answer so I can pick that as correct answer.

[Usce]

Amazing, thank you @pat2015 for taking time to provide a prompt answer and putting clarity on this topic!