Dual boot 15.4 and Windows 10

I carefully followed the instructions on this page

https://forums.opensuse.org/t/installing-windows-10-on-opensuse-leap-15-4-in-a-separate-partition/164576

When done it booted 15.4 but Win 10 was nowhere to be found. Ran os-prober with no result.

ion@ion-lifebooks936:~> sudo os-prober
ion@ion-lifebooks936:~> sudo fdisk /dev/sda

Welcome to fdisk (util-linux 2.37.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

This disk is currently in use - repartitioning is probably a bad idea.
It's recommended to umount all file systems, and swapoff all swap
partitions on this disk.


Command (m for help): p

Disk /dev/sda: 238.47 GiB, 256060514304 bytes, 500118192 sectors
Disk model: Micron_1100_MTFD
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x9828112a

Device     Boot    Start       End   Sectors  Size Id Type
/dev/sda1           2048   1026047   1024000  500M  7 HPFS/NTFS/exFAT
/dev/sda2        1026048  90519551  89493504 42.7G  7 HPFS/NTFS/exFAT
/dev/sda3  *    90519552  91133951    614400  300M  c W95 FAT32 (LBA)
/dev/sda4       91133952 500103449 408969498  195G 83 Linux

Command (m for help): q

ion@ion-lifebooks936:~> 

What went wrong?

It’s hard to guess without more information.

The usual reason that “os-prober” does not show Windows, is that one of your systems is using UEFI booting while the other is using BIOS/MBR booting.

If that is your only hard drive, then you seem to be using BIOS/MBR booting (there is no EFI partition). But we don’t know if that is your only hard drive.

Only one hard drive. sda3 is the EFI partition and it is set to boot.

This partition was most likely created by Linux install and your Windows is using legacy BIOS.

@ionmich ahh no, thats a Legacy system… Disklabel type: dos UEFI is type: gpt, is the system capable of UEFI boot?

@ionmich this is my dual boot laptop…

fdisk -l /dev/sda

Disk /dev/sda: 111.79 GiB, 120034123776 bytes, 234441648 sectors
Disk model: OCZ-VERTEX460A  
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 

Device         Start       End   Sectors  Size Type
/dev/sda1       2048    534527    532480  260M EFI System
/dev/sda2     534528    567295     32768   16M Microsoft reserved
/dev/sda3     567296  52996095  52428800   25G Linux filesystem
/dev/sda4   52996096  84453375  31457280   15G Linux filesystem
/dev/sda5   84453376  87599103   3145728  1.5G Linux swap
/dev/sda6   87599104 233170502 145571399 69.4G Microsoft basic data
/dev/sda7  233170944 234440703   1269760  620M Windows recovery environment

os-prober

/dev/sda1@/EFI/Microsoft/Boot/bootmgfw.efi:Windows Boot Manager:Windows:efi

Then I think that explains your problem.

As far as I know, Windows will only use BIOS/MBR booting with a DOS partitioned disk. However, a UEFI BIOS can still use DOS partitioning, and it seems that’s how you installed linux. So linux and Windows are using incompatible ways of booting.

If you don’t want to reinstall, then simplest would be to change openSUSE to use BIOS/MBR booting. Use Yast bootloader, and set it to use “grub2” rather than “grub2 for EFI”.

Thanks. I had already tried that, and selected “Probe other OS” but it didn’t find Win 10. It’s easy enough to reinstall both. How do I go about duplicating the malcolmlewis setup just above? In what order do I partition, format (GPT or not) and install?

@ionmich so the system can use UEFI? Check the system BIOS Setup…

Easiest would be to use “Guided Setup”.

When it asks what to do with existing partitions, set it to remove even if unneeded. In my test (in a virtual machine), it will then propose a GPT partition table. And you can continue from there.

Yes. Bios can be set to UEFI or CSM.

@ionmich then set to UEFI, I would suggest boot from a live usb and setup the disk, install windows and then Leap via the guided setup as indicated by @nrickert.

Make sure you set the /boot/efi partition and to not format.

Success at last. Thanks to everyone.