Solved Trying to setup Windows 10/11 dual boot

Before upgrading my Windows 10 Pro PC to Win 11 I would like to have a preview of it so I have been trying to set up a dual boot. I have created a partition for it on the boot disk, copied the ISO to a USB stick using Rufus and tried to install. At the point in the installation where it shows the available disk space I select the partition I prepared but get the message 'We couldn’t create a new partition or locate an existing one. For more information, see the Setup log files'. I have attached the Setup log file (the first I have ever looked at) but my interpretation of it is that at line 2349 it says it is validating the partition I have pointed it at on disk 2 (my boot disk) offset [0x6339600000]. On line 2362 it appears to say it is happy with that partition. It then says on line 2366 that it couldn't find any system volumes. I assume it is looking for the EFI system partition which is at disk 2 offset [0x0] which it says is too small at line 2378. The EFI system partition is 100MB and according to Minitool has 69.4MB unused.

All the examples I have seen online of dual booting 10 and 11 also show a 100MB EFI system partition so I assumed it would be big enough.

I have also attached a screenshot of Minitool. It calls the boot disk Disk 3, the intended partition for Win 11 shows as H: and is 68.36GB.

I hope that someone who is more familiar with Setup log files can advise on the reason for failure.

Hello @geoffd and welcome to ElevenForum.


Here is the dual boot tutorial...


There's a tutorial for just about everything on Ten Forums and Eleven Forum.




Another option is just make a full backup of Windows 10, and save it on a storage drive.
Then you can just upgrade Win 10 to Win 11, and play with it.
If you don't like Windows 11, you can always just restore the backup you made of Windows 10.

Thank you @Ghot. The method I have used is essentially Option 1 of the tutorial. A difference is that the tutorial leaves the space made for Win 11 unallocated rather than create a partition but I have also tried that.

geoffd said:

Thank you @Ghot. The method I have used is essentially Option 1 of the tutorial. A difference is that the tutorial leaves the space made for Win 11 unallocated rather than create a partition but I have also tried that.

Click to expand...

I would try Option #2.
FYI... step #9 directs you to another link, the Clean Install link.

I did it a different way. Since I have a desktop with a large case... I just got a 2nd SSD and installed Win 11 to that.
Well actually, I cloned my Win 10 install to the new SSD, then did an In-Place Upgrade from Win 10 to Win 11, on the new SSD.
When I want to switch between the two, I just change the cables.

I didn't want Win 10 and Win 11 sharing ANYthing.

Ghot said:

I did it a different way. Since I have a desktop with a large case... I just got a 2nd SSD and installed Win 11 to that.
Well actually, I cloned my Win 10 install to the new SSD, then did an In-Place Upgrade from Win 10 to Win 11, on the new SSD.
When I want to switch between the two, I just change the cables.

Click to expand...

I have a spare disk in the PC and thought of using that in a similar way but my existing Win 10 and boot disk is an M.2. I didn't want to have to remove it and I don't know if it can be disabled in the BIOS. According to a number of online tutorials the method I am using should work. Hopefully someone can make sense of the Setup log before I have to resort to a Plan B.

There are 3 disks in your screenie all with esp parts. The currently booted os is on disk 3 and is booted from the esp part on disk 3.

Setup appears unable to determine which is the best system partition.

Might be easier if you detach the other other 2 disks or directly apply the image to the target partititon instead of using the windows setup.exe rigmarole.

apply the image from install.wim/esd onto the 63gb partition with dism or dism++ or winntsetup or gimagex or just copy out the contents of the wim image onto the 63gb using 7-zip. Then add the bcd entry with command bcdboot h:\windows

if you use winntsetup it will run bcdboot for you after applying the image.




winntsetup

SIW2 said:

There are 3 disks in your screenie all with esp parts. The currently booted os is on disk 3 and is booted from the esp part on disk 3.

Setup appears unable to determine which is the best system partition.

Might be easier if you detach the other other 2 disks or directly apply the image to the target partititon instead of using the window setup.exe rigmarole.

Click to expand...

Thanks @SIW2 for the suggestion of detaching the other 2 disks! Not something I had thought of doing. I have just given it a try and it was then happy with the partition - no error message - and the installation started. I haven't time to complete the installation this evening (22:20 UK time) but it should be OK now.

I will run the installation again tomorrow and report back.

Just to confirm, with the other 2 disks detached I could install Windows 11 and now have a dual boot configuration. Thanks to @SIW2 for the suggestion. Also @Ghot - had I used the tutorial you referenced and took its advice to 'Temporarily disconnect all non OS hard drives' then it would have been OK. Looking back at the tutorials I did use, they only had a single disk drive!

geoffd said:

Before upgrading my Windows 10 Pro PC to Win 11 I would like to have a preview of it so I have been trying to set up a dual boot. I have created a partition for it on the boot disk, copied the ISO to a USB stick using Rufus and tried to install. At the point in the installation where it shows the available disk space I select the partition I prepared but get the message 'We couldn’t create a new partition or locate an existing one. For more information, see the Setup log files'. I have attached the Setup log file (the first I have ever looked at) but my interpretation of it is that at line 2349 it says it is validating the partition I have pointed it at on disk 2 (my boot disk) offset [0x6339600000]. On line 2362 it appears to say it is happy with that partition. It then says on line 2366 that it couldn't find any system volumes. I assume it is looking for the EFI system partition which is at disk 2 offset [0x0] which it says is too small at line 2378. The EFI system partition is 100MB and according to Minitool has 69.4MB unused.

All the examples I have seen online of dual booting 10 and 11 also show a 100MB EFI system partition so I assumed it would be big enough.

I have also attached a screenshot of Minitool. It calls the boot disk Disk 3, the intended partition for Win 11 shows as H: and is 68.36GB.

I hope that someone who is more familiar with Setup log files can advise on the reason for failure.

Click to expand...

Hi there
Easy way - use 1 or 2 or even 3 disks.

Simply create VHDX physical files. Attach these as "Disks " with Diskpart. Install OS'es via DISM /APPLY-IMAGE or clone from existing OS'es.

Install bootloader for each OS via bcdboot.exe

Now done e.g :



Windows 10, Windows 11 Std, Windows 11 Canary (ISL and ENG) no problem. Ive even a Windows PE system on it too.

Cheers
jimbo

Ghot said:

When I want to switch between the two, I just change the cables.

Click to expand...

Boot into bios menu and choose the right disk. No need to switch cables
I did that when trying out windows 11.

Now I have 2 windows 11 installation on 2 SSDs. I had some issues with Thunderbird in my working ssd (NVME) and was able to solve the problem by testing it on second windows 11ssd (SATA).

FDretired said:

Boot into bios menu and choose the right disk. No need to switch cables
I did that when trying out windows 11.

Now I have 2 windows 11 installation on 2 SSDs. I had some issues with Thunderbird in my working ssd (NVME) and was able to solve the problem by testing it on second windows 11ssd (SATA).

Click to expand...

I know that's possible. I didn't WANT to do it that way.
I wanted Windows 10 and Windows 11 to NEVER be physically hooked up at the same time.

jimbo45 said:

Hi there
Easy way - use 1 or 2 or even 3 disks.

Simply create VHDX physical files. Attach these as "Disks " with Diskpart. Install OS'es via DISM /APPLY-IMAGE or clone from existing OS'es.

Install bootloader for each OS via bcdboot.exe

Now done e.g :

View attachment 80126

Windows 10, Windows 11 Std, Windows 11 Canary (ISL and ENG) no problem. Ive even a Windows PE system on it too.

Cheers
jimbo

Click to expand...

I'm with @jimbo45 on the Multi-Boot Option.

Here is mine:

jimbo45 said:

Simply create VHDX physical files. Attach these as "Disks " with Diskpart. Install OS'es via DISM /APPLY-IMAGE or clone from existing OS'es.

Install bootloader for each OS via bcdboot.exe

Click to expand...

Thanks @jimbo45 . I now have my dual boot but I don't think I will be able to resist exploring that approach. Something for the dark cold nights.