Adding a second bootable drive initialise as MBR or GPT?

Question

I recently brought a new PC with a 1tb ssd (GPT) the bios is UEFI . I have installed windows 11 on that disk. I have added a 2tb hdd drive which I have not yet initialised. as its asking whether I want the new drive to be MBR or GPT, Can’t remember ever being asked that before so did a search to see which to use. The results were both confusing and conflicting.

The intention was to put 2 partitions on the new drive. 1 for a bootable copy (clone(?)) of the existing drive and one for data. The thinking being that in years to come should I want to do a “clean install” I can clone it back onto the ssd. Or should that ssd fail I can boot to the hdd while I’m waiting to get a new ssd and then clone it onto that. Should I ever need to boot from the hdd I was going to use F12 and select the boot drive from that. The only time I would need to do it would be either to check that the cloning worked or install any updates from time to time.

But the search results have got me confused and worried that this is not possible. Some of the confusion could be from my understanding where people trying to INSTALL a second instance rather than make a cloned copy.

Search results that are causing me most concerns

1. they say you can’t have 2 GPT bootable systems on the same PC
2. if you have more than 1 EFI partition then windows updates can get confused and cause corruption so you should delete any secondary EFI partitions. But that surely would make that disk unbootable if the ssd was to fail.
3. If you try to boot from a different drive windows 11 will still use the EFI from the last boot rather than the EFI from the selected drive. This would mean that your not really checking that that drive is truly bootable and if booted into it purely to get system updates they may not be installed correctly.

So is it OK to initialise it as GPT or should I initialise it as MBR to avoid any EFI conflicts. But would I then be able to clone it back onto a GPT drive.

Answer 1

Hello ABN, I am Henry and I want to share my insight about this issue.

Based on what you've shared, I recommend initializing your new 2TB HDD as GPT.

Since your PC uses UEFI firmware, GPT is the modern partition standard optimized for it. Using MBR on a UEFI system for a bootable drive is a step backward and may introduce complications. The issues you've read about are not caused by GPT itself but rather by how multiple bootable Windows installations interact—something that can be easily avoided.

About your concerns:

1. "Can't have 2 GPT bootable systems": This is a misconception. You can have them, but the Windows Boot Manager can get confused, leading to the next problem.
2. "Multiple EFI partitions cause corruption": This is absolutely true and is the main reason to avoid your original plan. When Windows Update runs or boot repairs are attempted, the system can write to the wrong EFI partition, potentially corrupting one or both of your bootable drives.
3. "Windows uses the EFI from the last boot": This is also correct. Even if you boot from the HDD via the F12 menu, the running OS might still reference or try to update the primary SSD's EFI partition, leading back to the corruption risk.

Given these risks, I recommend create a System Image instead of creating a second bootable drive (a clone)

I do compare for your better and safer:

Feature	Cloned Drive	System Image
How it's stored	A fully functional, bootable drive with its own hidden boot partitions (EFI).	A single, large file (like WindowsImageBackup) stored on a normal data partition. No hidden boot partitions.
Risk of Conflict	High. The computer sees two "master" boot drives. Windows Update can write to the wrong one, corrupting your system.	Zero. The computer sees only one boot drive (your main SSD) and one data drive (your HDD). The backup file is just data; the PC doesn't try to boot from it.
How you recover	You physically swap the drives or go into the BIOS (F12) to boot from the second drive.	You boot from a separate Windows Recovery USB drive, point it to the image file on your HDD, and it restores the entire system onto a new or repaired SSD.
Flexibility	Less flexible. The clone is tied to the exact size and state of the original drive at the time of cloning.	More flexible. You can store multiple system images over time on the same partition.

Hope this helps you.

Answer 2

For Windows 11 there is only BIOS UEFI for supported installations.

That is UEFI native (without CSM)

For Windows 10 there were BIOS options for Legacy or UEFI native or UEFI hybrid (with CSM).

A BIOS that is Legacy will have a default Windows drive with a MBR partition.

A BIOS that is UEFI will have a default Windows drive with a GPT partition.

All other drives (non-Windows drives) can be MBR or GPT (storage drives).

A storage drive with MBR partition can be moved from a computer with BIOS Legacy to a computer with BIOS UEFI.

A storage drive with GPT partition can be moved from a computer with BIOS UEFI to a computer with BIOS Legacy.

If you want to have an additional Windows bootable drive it should be GPT.

The GPT drive by default will have an EFI FAT32 partition to boot with BIOS UEFI native (without CSM).

This is dual booting.

.

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Power outages / surges can injure multiple drives.

One of the quickest methods to recover from a failed drive is to replace the drive and restore a backed up image.

Microsoft had deprecated backup imaging.

There are third party software that can be used for making backed up images.

(Acronis, Aoemi, EaseUS, Hasleo, Macrium, Paragon, etc.)

There are free and pay versions.

The backed up images can be saved to another drive or the cloud or both.

One or more of these links may be useful:

https://learn.microsoft.com/en-us/windows-hardware/manufacture/desktop/hard-drives-and-partitions?view=windows-11

https://learn.microsoft.com/en-us/windows-hardware/manufacture/desktop/configure-biosmbr-based-hard-drive-partitions?view=windows-11

https://learn.microsoft.com/en-us/windows-hardware/manufacture/desktop/configure-uefigpt-based-hard-drive-partitions?view=windows-11

https://learn.microsoft.com/en-us/windows-hardware/manufacture/desktop/configure-more-than-four-partitions-on-a-biosmbr-based-hard-disk?view=windows-11

https://learn.microsoft.com/en-us/windows-hardware/manufacture/desktop/windows-and-gpt-faq?view=windows-11

Answer 3

Thank you for your detailed and helpful replies.

Before I go any further can I explain that I’m 75yrs old and finding it a little difficult to learn how to do these things that used to be very easy. I dread to think what will happen if I need to do it again in 10yrs time.

I can see the advantages of creating system images as I can easily update from time to time as things / usage change thus keeping the potential restore current.

Main downside as I see it is that should the PC stop working I can’t simply just boot from a cloned drive to ensure that the crash is simply SSD related and I will need to wait until a new SSD is brought and installed before being able to try and use the computer again.

Since I couldn’t get networking working I brought an 1tb external usb HDD which I will use to transfer the data from my old system to the new one.

The intention was to then use it to create a bootable clone of my laptop so should that drive fail I can still use it.

So the next questions which I probably should have asked before getting it are

1. can I actually use that external drive to make a bootable clone of the laptop?
2. can I use it to have a bootable clone of the laptop and the main PC?
3. Failing the above can it have 2 separate Windows Recovery USB drives one for the laptop and one for the PC

Sorry to be such a pain and thank you once again

Answer 4

Please ignore the last post was suffering from tunnel vision still thinking about my original idea. Having got my head around the new idea it have created a new thread to discuss using the system image. Hope that’s alright.