Unable to install a second Windows to my multi OS system

[Gary Seven]

Hello everyone, here's the background.

I currently have a desktop machine with a mix of ssd's, HD's, and NVME drives installed (six in total). Up to now I have been using BUI (v2) to boot Windows 10, and four different Linus distros each on their own dedicated drive. My setup is that I have BIU installed to the same drive as Win10, which I will refer to as Sda2 (so that means the ESP and Win10 on that drive, plus my BIU installation).

After testing Windows 11 IoT in a virtual machine for several months, I decided it was time to install it to a dedicated drive for some bare metal testing. However, all attempts to install Windows using the usual BIU "technique" have failed, and I can't figure out why. As always, in the BIU interface I create a new partition on the target drive, reboot out of BIU and into my BIOS, chose the Win11 install USB and start the installation. The process proceeds as it should, with Windows copying files and all that jazz until it gets to the point where it reboots to "continue the installation." At this point the installation fails with the computer just going into a continual reboot loop. Once I take control I get back into BIU, I see that a new Boot Item has been added with the (correct?) path \EFI\Microsoft.002\boot\bootmgfw.efi. This makes sense as my original Windows10 installation is assigned "Microsoft.001".

But that's it. Trying to boot into Windows 11 just brings up a "Windows installation encountered an unexpected error" message, and after several tries it also complained about \Windows\system32\winload.efi not being found.

What am I doing wrong? Is it even possible to install another version of Windows (using the same common ESP) with BIU? Let me know what other information you need. Thank you!

[TeraByte Support]

is there free space in the EFI System partition or did it run out?

[Gary Seven]

The ESP is 1 GiB in size. Currently, about 62MiB (or about 6%) is occupied. Plenty of space here.

[TeraByte Support]

then you should be good to go, if you don't reactivate BIU it's booting just as a normal Win11 install would do.

The key is to always boot back to BUI then boot to the installation media (no matter the OS being installed).

I would try letting Win11 create the partition as well to see if it makes a difference, on GPT it's safe since nothing hidden from complete view.

Searching online shows that for Win11 installs, that message isn't that uncommon.

[Gary Seven]

But that is what I was doing. That is, once Win11 went into the first reboot after installation of files and then the reboot went into a loop, I forced a hard reboot of the machine, went into my bios, choose the BootIt UEFI boot option, booted back into the BIU interface, and found that a a new Win11 Boot Item had been written. Trying to boot back into the Win11 install from there fails. Also, rebooting back into the BIOS and choosing the Win11 installation USB drive just brings me back to the original Windows 11 Install starting point, instead of a continuation of the installation.

Yes I will try to let Win11 create the partition and see what happens. It's all just such weird behavior.

[Brian K]

Gary,

So the Win11 install never finishes? You don't get to a Win11 desktop with a Recycle Bin and a few other icons?

[Gary Seven]

Gary,

So the Win11 install never finishes? You don't get to a Win11 desktop with a Recycle Bin and a few other icons?

Hey Brian (long time no see)! Yes that's what was happening. See my next post for SOLVED.

[Gary Seven]

SOLVED

then you should be good to go, if you don't reactivate BIU it's booting just as a normal Win11 install would do.

The key is to always boot back to BUI then boot to the installation media (no matter the OS being installed).

I would try letting Win11 create the partition as well to see if it makes a difference, on GPT it's safe since nothing hidden from complete view.

Searching online shows that for Win11 installs, that message isn't that uncommon.

Hey Terabyte Support, I'm going to mark this down as SOLVED. I'm not 100% sure, but I think your suggestion of creating the partition via Windows 11 setup routine (versus doing it with Partition Work inside BIU) made the difference. Tbh I was afraid of doing this as I know it was a no-no in the MBR days, but hey thanks TONS for pointing me in the right direction to solve this hair pulling delay. Love this product!

Update to my original issue: After a lot of experimenting and several test installations later, it occurred to me that the problem at hand was due to the location of the small (16 MB), Microsoft Reserved Partition. In all my successful test Win10/11 installations this partition has always been located BEFORE the actual OS partition. However, when I used Partition Work to create an OS install partition to later choose in the Windows Installation Setup page, what would happen is Windows would happily accept my choice and then later create its Microsoft Reserved Partition AFTER the OS partition. In every case this particular arrangement would fail. So it's just my 2 cents worth here, but either one must create the 16MB MRP before the creation of the OS partition whilst in Partition Work of BIU, or better just to let Windoze do it during the install/setup phase.

[Brian K]

Gary,

If you created a NTFS partition on a blank empty drive then that drive was still a MBR disk. The Windows install then had to create a GPT disk.
I always let BIU create a GPT disk first and then create a NTFS partition for the Windows install. Never had an issue with creating the partition in BIU.

[Brian K]

Gary, an interesting test.

128 GB SSD. Blank. It was converted to GPT in BIU and a MSR was now seen at the beginning of the drive. The MSR was Slid to the end of the drive. A 100 GB NTFS partition was created and the MSR was slid up to the end of the NTFS partition.

Win11 was installed to the NTFS partition.
No problem. Win11 booted.

In BIU PartWork the NTFS partition had been resized smaller and there was a 642 MiB Recovery partition, then the MSR.

So Win11 works with the MSR before or after the NTFS partition.