Reinstalling Windows on dual boot system

[makem2]

The bios tells me the hard drive is booted in UEFI mode but I do not see how to find where there is an option to choose between windows and ubuntu.

[CelticWarrior]

It's in the Boot menu or equivalent. Every firmware is different. Again, where you find "Windows bootloader manager" navigate to it and press Enter (or follow your firmware's specific instructions), other boot options should be listed there.

Yes, this requires some effort in reading about boot process requirements and your own manual (~5min). If you're installing any OS you don't have the luxury of ignoring basic aspects of the process.

[makem2]

If it is windows 8.1 or 10 then fast boot is on, disable it in windows. Boot to you ubuntu USB install boot repair and use pastebin to paste output, no repair yet. Let these people see what you are working with first. https://help.ubuntu.com/community/Re...tallingWindows

https://paste.ubuntu.com/p/rGX8mdccsb/

Edit: Booting into the live usb shows an error:

Check finished: errors found in1 files! You might encounter errors.

[CelticWarrior]

Your summary report clearly shows all the required bootloaders for Windows and Ubuntu present in the ESP, as it should be.
Furthermore, as expected. it shows the following boot order:

BootOrder: 2001,0004

where 2001="EFI USB Device" (perfectly normal considering you're booting a live session from an external USB media) and 0004="Windows Boot Manager" exactly as expected.

So, again as suggested, you should disable Windows Fast Startup feature as that creates issues for dual-booting and even Windows standalone. Then, for the third time in this thread, all you need to do is change the boot stanza back to "Ubuntu" instead of "Windows bootloader manager".

[makem2]

Your summary report clearly shows all the required bootloaders for Windows and Ubuntu present in the ESP, as it should be.
Furthermore, as expected. it shows the following boot order:

BootOrder: 2001,0004

where 2001="EFI USB Device" (perfectly normal considering you're booting a live session from an external USB media) and 0004="Windows Boot Manager" exactly as expected.

So, again as suggested, you should disable Windows Fast Startup feature as that creates issues for dual-booting and even Windows standalone. Then, for the third time in this thread, all you need to do is change the boot stanza back to "Ubuntu" instead of "Windows bootloader manager".

I am still searching for Windows bootloader manager option which is not in bios.

I will check pastebin for your clue 004=windows boot manager which may help me find it

Fast boot was disabled and I see windows boot manager is on sdb2 but I don't see how to access it to change it.

[makem2]

Please, advise me where/how to find and edit the boot stanza from either windows or the live ubuntu usb.

Once I find it I will change it.

[CelticWarrior]

First of all, it's in the UEFI ("BIOS") settings > BOOT menu, not in any OS. And surely there aren't that many places where it could be that you miss it.

But it can be managed by software tools thanks to the UEFI improvements over the obsolete BIOS. If you could boot Ubuntu then you would use 'efibootmgr'. From Windows which is the OS you can boot now, there's third-party tool that can be used, EasyUEFI.

[makem2]

First of all, it's in the UEFI ("BIOS") settings > BOOT menu, not in any OS. And surely there aren't that many places where it could be that you miss it.

But it can be managed by software tools thanks to the UEFI improvements over the obsolete BIOS. If you could boot Ubuntu then you would use 'efibootmgr'. From Windows which is the OS you can boot now, there's third-party tool that can be used, EasyUEFI.

There are only two place to look in the bios, Boot priority option and system configuration

Boot priority:

usb
hdd/ssd
lan
odd

System configuration:

Boot Mode: UEFI boot or CSM boot

No place that windows boot manager could hide

I will try the efibootmgr from the usb

[makem2]

xubuntu@xubuntu:~$ efibootmgr
BootCurrent: 0003
Timeout: 0 seconds
BootOrder: 2001,0004,0002,2003,2002
Boot0000* Realtek PXE
Boot0001* Realtek PXE
Boot0002* ubuntu
Boot0003* EFI USB Device (ASIX AX88772 USB Fast Ethernet Controller)
Boot0004* Windows Boot Manager
Boot0007* Realtek PXE
Boot0008* Realtek PXE
Boot0009* Realtek PXE
Boot000A* Realtek PXE
Boot000B* TOSHIBA MQ02ABD100H             
Boot0015* Realtek PXE
Boot0016* Realtek PXE
Boot0017* ubuntu
Boot0018* ubuntu
Boot0019* Realtek PXE
Boot001A* ubuntu
Boot001B* ubuntu
Boot2001* EFI USB Device
Boot2002* EFI DVD/CDROM
Boot2003* EFI Network
xubuntu@xubuntu:~$

I see where I can change Windows Boot Manager to ubuntu but 'how' is not obvious. I have to find that boot file and edit it using nano in my case.

I prefer to make the change using ubuntu not third party windows if I can find how!

[makem2]

Using the third party tool I booted xubuntu into emergency mode.

I am loath to ask for help in this thread so will go try to find where to go from here so as not to risk messing up.

Thank you for the assistance.

EDIT: Checking the journal show errors related UEFI so maybe am in the right thread?

Couldn't get size: 0x800000000000000e

and

MODSIGN: Couldn't get UEFI MokListRT

There are thousands of lines - is it suitable for pastebinit and ask for assistance ?