Partitions are corrupted

Thanks for the link. I got fairly good support from Sonny at support@supermicro.com but he didn't understand (nor did I) the issue with the Windows partitions that you know about.

From the Manual page 4-43 you launch the boot override from BIOS

When you did a Clean Install:
- Did you delete ALL partitions till you have one and only one unallocated space?
- Did you detach ALL other drives, leaving on only the target drive?

Reset BIOS or load defaults.
Set Disk mode to AHCI, not RAID
Select OS mode = UEFI or Select OS mode = other + UEFI (depends on BIOS).
Disable fast boot and secure boot (you can turn it on after installation)

Windows can be installed in two ways: Legacy-MBR or UEFI-GPT
To install as Legacy-MBR you must boot the installation drive as Legacy
To install as UEFI-GPT you must boot the installation drive as UEFI.

If you have a UEFI BIOS, you should install as UEFI-GPT
Detach any other drives (SATA or Power cable) from the MB.

During POST, press F11(?) to launch the boot menu. You will see two options for the USB drive. USB UEFI (Name) and USB (Name). Select USB UEFI (Name) if you want to install as UEFI-GPT or select USB (name) if you want to install as Legacy-MBR.
Go to install and delete ALL partitions on the main drive till you have one and only one unallocated space and then proceed.
If you don't want to use MS account, don't enable updates or connect to the internet during installation.

Mega: Your post looks very interesting. I will work on this, likely the coming weekend. Today I tried the following idea from Macrium Reflect tech:
I am posting the result so that you, SIW2 and other experts can see where I stand.
Boot into Macrium Reflect Windows PE. Open a Windows command window. To open a command window click the icon on the taskbar.
Type: diskpart
Type: list disk
Select the disk number that you want to restore to. For example:select disk 0
Clean the selected disk: cleanBy default, "clean" creates an empty MBR disk.
Convert it to GPT:convert gpt
Create the EFI partition: create partition efi size=200Format the EFI partition:
format fs=fat32
Create the MSR partition:
create partition msr size=128
Exit Diskpart: 2/28/23
I did up to here successfully. Since I don't have the restore files anymore, I again tried Windows 10 install from usb stick to no avail. I still boot into EFI Shell.

There is clearly some kind of disconnect between the BIOS and the internal HDs, since Windows Boot Mgr never shows up in BIOS.

cma6 said:

Mega: Your post looks very interesting. I will work on this, likely the coming weekend. Today I tried the following idea from Macrium Reflect tech:
I am posting the result so that you, SIW2 and other experts can see where I stand.
Boot into Macrium Reflect Windows PE. Open a Windows command window. To open a command window click the icon on the taskbar.
Type: diskpart
Type: list disk
Select the disk number that you want to restore to. For example:select disk 0
Clean the selected disk: cleanBy default, "clean" creates an empty MBR disk.
Convert it to GPT:convert gpt
Create the EFI partition: create partition efi size=200Format the EFI partition:
format fs=fat32
Create the MSR partition:
create partition msr size=128
Exit Diskpart: 2/28/23
I did up to here successfully. Since I don't have the restore files anymore, I again tried Windows 10 install from usb stick to no avail. I still boot into EFI Shell.

There is clearly some kind of disconnect between the BIOS and the internal HDs, since Windows Boot Mgr never shows up in BIOS.

You don't need to use diskpart.
If you boot the Win 10 USB installation drive as UEFI, delete all partitions and then proceed it will initialize the drive as GPT and will install as UEFI-GPT.
I don't know how did you created the Win 10 USB installation drive. - Let MCT create the Win 10 USB installation drive. You need a 8G (or bigger) flash drive.

Hi Mega:
I tried your ideas today. I first unplugged the two internal SSDs (physical disks 2 & 3). In BIOS, I noted that a BIOS Feature/Re-try Boot was set to "EFI Boot", though it could have been Legacy.
In UEFI mode I booted into the Windows Installation stick, which showed only Drive 0 (a good thing).

Partition 1 200 MB System; Partition 2 128 MB MSR (Reserved); Partition 3 unallocated 372 GB. I chose Partition 3. The Windows installation completed successfully.

I removed the Win 10 Installation USB stick and went into BIOS, which did not show "Windows Boot Mgr, a bad sign. Boot menu showed "UEFI USB Hard Disk" and "UEFI Hard disk" among others. When I rebooted, system went immediately into EFI Shell. No success.
I went into Legacy Mode in BIOS and tried Windows installation. It refused to install on Partition 3 because is was MSR, not GPT.

To install as UEFI - GPT you must:
- Boot the Win 10 installation drive as UEFI so the installation drive must be Fat32 not NTFS
- You must delete all partitions on the drive till you have one and only one unallocated space and then proceed. When you delete all partitions it guarantees that the drive will be initiated as GPT and it will install as UEFI - GPT

I don't understand. I did boot in UEFI mode and did install into the unallocated space. How does one " delete all partitions on the drive till you have one and only one unallocated space and then proceed"?
I did not see that option in the Windows Install boot media program?
Thanks, CMA

Thanks, I didn't see that "Drive options (advanced), but I used Diskpart to clean Disk 0 so that I now have only one unallocated space on Disk 0.
I then tried Windows Clean install again. It completed successfully, but still no luck--still boots immediately into EFI Shell.
Does Windows install Windows Boot Mgr. on the HD? Because if not, then maybe Windows Boot Manager is missing from the BIOS chip where it should be on this system.
Is it possible to install or copy Windows Boot Manager onto the HD partition where I just installed Windows. The Macrium Reflect PMAP USB stick hold 3 files that may be relevant: bootmgr 407 KB; bootmgfw.eft (EFI file) 1522 KB; and bootmgr.efi (EFI file) 1535 KB.

(Unfortunately I also cleaned one of my Reflect recovery USB sticks and now cannot format the 64 GB stick.)