Solved How to unscramble a dual-boot system

I need some advice on how to unscramble this scenario. I upgraded in-place from Windows 10 to 11, but without keeping files, apps, etc. I ended up with some issues and against my better judgment decided to reinstall using an ISO on usb . Because I have 3 1TB SSDs in my system, I accidentally selected the wrong one for the second installation. The original C drive from the first installation is now "J" and the new one for the second installation is now "C". See pictures.

Upon startup, I'm presented with a dual-boot menu and both open to their respective Windows 11 desktops. My ideal situation now would be to somehow switch drive J with drive c. I would then reformat what is now C and use it for more storage. C now shows it has the boot info, but J has the UEFI and recovery partitions. If this is too complicated, I can just leave things as they are as I have adequate storage,. Disregard Drive M in the pictures; it's just a mechanical storage drive.

I am really confused. Which disk number do you want the computer from? Disk 0 or Disk 2?

From what I understand, you want what occupies New Volume C on Disk 0 to occupy volume J on Disk 2?
if so, you could clone C to J using a program like Macrium Reflect Free.


In Disk Management, you would need to right-click C and select shrink volume (the source can't be larger than the destination)

Thanks for the replies, guys. Let me see if I can explain this a little further. Drive C (Disk 0) is the second installation of Windows 11 that I don't want as it's on a slower SSD. Drive J (Disk 2) is the faster NvME SSD and is the original copy of Windows 11 and used to be the C drive. What I'm wondering is do both drives have a boot record? In other words, can I boot up to the copy of Windows that's on Drive J (the original installation) and from there simply reformat drive C and use for storage? I obviously don't need 2 copies of Windows 11. I've never tried to reformat a drive C (disc 0) from within Windows, but if I've booted up to Windows using Drive J, it sounds like it might be possible, but I wanted to ask you guys first. It looks like C is just one large partition. Once I'm able to reformat C, I can change it's drive letter and J would then become C and the only copy of Windows. Since J is the original installation of Windows 11, I assume it would have the boot record and all the files it needs to boot. If I can't reformat C within Windows even booting up from the other drive, could I do it in diskpart> So, I don;' want to move data from C to J, I want to reformat C altogether. Hope I've explained this better.

Start Windows on your faster NVME disk through the bootmanager. Windows will then automatically assign drive letter C: for it. From there you can then format the other drive.
The bootmanager itself can be removed later by booting into WinPE eg from the installation media and running some appropriate commands from a command window. I don't have the exact commands at hand, was something with fixmbr .. but it will depend if you have GPT or MBR. Probably someone else here in the forum can help further with that - or maybe there is even a tutorial from @Brink

bzw recently I had the same with two parallel Win11 installs, one was on a SSD, one on a HDD. Wanted just to keep the one on the SSD adn also got rid of the boot manager screen so now PC starts with the SSD :)

Hello nitewulf,

Are you wanting to change the default OS to load at startup?


Afterwards, you could safely delete the OS you don't want.

Brink said:

Hello nitewulf, :)

Are you wanting to change the default OS to load at startup?

Choose Default Operating System to Load at Startup in Windows 10

How to Choose a Default Operating System to Load at Startup in Windows 10

www.tenforums.com

Afterwards, you could safely delete the OS you don't want.

How to Delete Boot Loader Entry on Boot Menu at Startup in Windows

How to Delete Boot Loader Entry on Boot Options Menu at Startup in Windows If you have more than one operating system installed on your PC, you will see a Choose an operation system (Windows Boot Manager) screen at startup with the name (description) of e

www.tenforums.com

Click to expand...

Brink, my goal was to get rid of the second installation of Windows 11 and I just fixed it taking the easy way out. I simply removed the older SSD that contained the 2nd installation of Win11 from my computer. I replaced it with a spare SSD I had lying around and that will be for storage. Now I can fool around with the SSD I removed and attach it to a cable and reformat it using diskpart when I have the time. So I'm good to go now except for the dual boot-loader entry and with your tutorial, I'm sure I can figure that out. So now I'm back to my original C drive. Thanks everyone for their help.

Okay, so you just wanted to switch the drive letters around, cool. As for the boot loader, EasyBCD 2.4 can do wonders.

I had no trouble fixing the bootloader. I did find that I was missing a couple of apps from the Microsoft Store and I ended up having to do a system restore back a couple of days, but I'm back up and running and everything appears to be working normally.

Hi there
OK I see you've fixed it -- but for others -- or next time the easy way is to boot say winpe or macrium free stand alone recovery media then
1) in the command mode type bcdedit (macrium free has a console option on bottom taskbar), winpe boots into console mode if using winpe media.
2) type bcedit with no parameters - this will display a list of the OS'es so look for the OS you want to get rid of -- it will be in between the { } with either {default} or { a long guid }
3) copy the guid and the {} so copy the whole string -- if you type manually you will probably make a mistake(ctrl C)
4) bcdedit /delete {the guid or default} - use ctrl-v to paste the guid string including the {} into the command after the /delete
5) job done

Don't do it from your running version of windows because that can hose it all up !!!! although it might work. It's safer to use winpe or something like macrium free to do this.

BTW with bcdedit you can also change default OS or change the description to a more useable name than just say W11 if you have several versions etc

bcdedit /set {the guid} description "Your own description" . This will appear in the boot menu on your next boot.



Q.E.D !!

Cheers
jimbo

Thanks, jimbo. I guess I got a little cold feet. I will study up on bcdedit and I also want to download Macrium Reflect as I need to have periodic good backups of my system. I have 2 old core 2 duo laptops running Windows 10 that I use as test machines and backups. The first thing I want to do is wipe that 1TB SSD I removed from the computer using an external SATA cable. Yhanks for yours and everyone else's help.