Dual Boot with Windows 10

Hello!
I recently installed OpenSUSE on my PC that already had Windows 10 installed. Usually Linux is cleaver and detects the other OS. This did not happen this time. I have 2 Ms.2 drives in my PC and my Windows install is on the other one. Could that be why it is not detected? Can I somehow manually add Windows 10 as a boot option from Leap 15.2? As it is now I have to be fast and press F8 and select the other drive to boot Windows 10 and this is easy to forget.

Best regards
Hoff

I can only guess, given the limited information.

My best guess: one of your systems (Windows or openSUSE) uses legacy MBR booting while the other uses UEFI booting. Those two are not mutually compatible, so if you mix them you will not be able to boot Windows from the grub menu.

Thank you! This would explain it.
OpenSUSE uses UEFI for sure so Windows 10 must be MBR then. Somehow this will have to be rectified.

EDIT:
I’m sorry I didn’t provide more information, I wouldn’t know how really. Well I know a little more now. :slight_smile:

Another reason could be an uncommented GRUB_DISABLE_OS_PROBER=“true” in /etc/default/grub. If so, use YaST2 bootloader to change the probe other OS box to true, and Windows should show up on next boot.

Thank you for your reply!
GRUB_DISABLE_OS_PROBER is set to “false” :slight_smile: So it has to be that MBR thing.

It should be set to true, I have to do this sometimes on tumbleweed, which is dual boot with win 10.

I go into yast, go to boot settings, and make sure, the box detect foreign OS is checked,

Then I click oke so it gets saved.

Hi!
I did that and it didn’t work.

So I decided on fresh installing Win10. But a problem occurred:
Since the driver was on MBR and not GPT I cannot install Windows 10 on that partition. It complains about it being MBR and therefor cannot be installed on there.
I have deleted or formatted the partition again and again but it remainse a MBR partition.

Is there a way to convert a single partition to GPT? Will I have to erase both partitions to convert the whole drive?

GPT is a partitioning system for the entire drive. You cannot just change one partition.

It is possible to have hybrid partitioning (really GPT but looks enough like MBR to fool some software). But this is usually not recommended.

Multi boot works best with every drive being converted to gpt and Compatibility Support Modus being disabled. Information given by you is somehow poor. You may show partitioning of your drives:

**erlangen:~ #** fdisk -l 
**Disk /dev/sda: 3.64 TiB, 4000787030016 bytes, 7814037168 sectors**
Disk model: WDC WD40EZRX-22S 
Units: sectors of 1 * 512 = 512 bytes 
Sector size (logical/physical): 512 bytes / 4096 bytes 
I/O size (minimum/optimal): 4096 bytes / 4096 bytes 
Disklabel type: gpt 
Disk identifier: 27C8C52A-8091-403C-ADF1-E9C791667D40 

**Device****     Start****       End****   Sectors**** Size****Type**
/dev/sda1       16384   67119103   67102720   32G Linux filesystem 
/dev/sda2    67119104  134223871   67104768   32G Linux filesystem 
/dev/sda3   134223872 7757789183 7623565312  3.5T Linux filesystem 
/dev/sda4  7757789184 7814037134   56247951 26.8G Linux filesystem 


**Disk /dev/sdc: 465.76 GiB, 500107862016 bytes, 976773168 sectors**
Disk model: Samsung SSD 850  
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: 90C1973B-4A41-4E96-85BA-B7358EA77CCC 

**Device****    Start****      End****  Sectors****  Size****Type**
/dev/sdc1       2048    208895    206848   101M EFI System 
/dev/sdc2     208896  63119359  62910464    30G Linux filesystem 
/dev/sdc3   63119360 126033919  62914560    30G Linux filesystem 
/dev/sdc4  126033920 512202751 386168832 184.1G Linux filesystem 
/dev/sdc5  512202752 638033919 125831168    60G Linux filesystem 
/dev/sdc6  638033920 700948479  62914560    30G Linux filesystem 
/dev/sdc7  700948480 734502911  33554432    16G Linux swap 
/dev/sdc8  734502912 793495551  58992640  28.1G Linux filesystem 
/dev/sdc9  793495552 852088831  58593280  27.9G Linux filesystem 
/dev/sdc10 852088832 852121599     32768    16M Microsoft reserved 
/dev/sdc11 852121600 976773119 124651520  59.4G Microsoft basic data 


**Disk /dev/sdb: 1.82 TiB, 2000398934016 bytes, 3907029168 sectors**
Disk model: CT2000BX500SSD1  
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: 24B476D2-CC39-4F91-9828-2024B84EFED2 

**Device****Start****       End****   Sectors**** Size****Type**
/dev/sdb1   2048 3907028991 3907026944  1.8T Linux filesystem 


**Disk /dev/nvme0n1: 476.94 GiB, 512110190592 bytes, 1000215216 sectors**
Disk model: Samsung SSD 950 PRO 512GB                
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: A84F222E-0177-499B-A7EA-BDA6F31E2196 

**Device****    Start****       End****  Sectors****  Size****Type**
/dev/nvme0n1p1      2048     206847    204800   100M EFI System 
/dev/nvme0n1p2    206848   25806847  25600000  12.2G Linux filesystem 
/dev/nvme0n1p3  25806848  134207487 108400640  51.7G Linux filesystem 
/dev/nvme0n1p4 134207488 1000214527 866007040 412.9G Linux filesystem 
**erlangen:~ #**

Are your m.2 drives sitting on the motherboard?

Check boot mode by running:

**erlangen:~ #** ll /sys/firmware/efi 
total 0 
-r--r--r--  1 root root 4096 Mar  2 07:22 config_table 
drwxr-xr-x  2 root root    0 Feb 27 09:41 **efivars**
-r--r--r--  1 root root 4096 Mar  2 07:22 fw_platform_size 
-r--r--r--  1 root root 4096 Mar  2 07:22 fw_vendor 
-r--r--r--  1 root root 4096 Mar  2 07:22 runtime 
drwxr-xr-x 12 root root    0 Mar  2 07:22 **runtime-map**
-r--------  1 root root 4096 Mar  2 07:22 systab 
drwxr-xr-x 66 root root    0 Mar  2 07:22 **vars**
**erlangen:~ #**

Thank you for your reply.
Yes they are sitting on the motherboard. The problem has since been solved! Windows 10 was too unstable and I’m now running just Leap 15.2