Arch Linux

clxxiii

Member

Registered: 2022-12-12

Posts: 2

[SOLVED] os-prober not detecting the windows partition

Hello!
Starting using Arch Linux a few weeks ago, and I'm enjoying it so far.
After playing around with it on a secondary tower PC, I decided to take the hard drive and put it into my main PC, so I could use it as a dual boot. I got both boots working perfectly, but I haven't figured out how to get GRUB to detect the windows partition.

Here's the output of sudo fdisk -l:

Disk /dev/sda: 465.76 GiB, 500107862016 bytes, 976773168 sectors
Disk model: WDC  WDBNCE5000P
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: 0x0a2efac0

Device     Boot     Start       End   Sectors   Size Id Type
/dev/sda1  *         2048   1126399   1124352   549M  7 HPFS/NTFS/exFAT
/dev/sda2         1126400 975700904 974574505 464.7G  7 HPFS/NTFS/exFAT
/dev/sda3       975702016 976769023   1067008   521M 27 Hidden NTFS WinRE


Disk /dev/sdb: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: TOSHIBA DT01ACA1
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: 9FCEB65C-B499-4C23-9710-72D98358B374

Device      Start        End    Sectors   Size Type
/dev/sdb1    2048     264191     262144   128M EFI System
/dev/sdb2  264192 1953523711 1953259520 931.4G Linux filesystem


Disk /dev/sdc: 1.82 TiB, 2000398934016 bytes, 3907029168 sectors
Disk model: ST2000DM006-2DM1
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: F1AFDD51-79AD-40E1-9789-2116D477A027

Device          Start        End    Sectors  Size Type
/dev/sdc1        2048     923646     921599  450M Windows recovery environment
/dev/sdc2      923648    1128447     204800  100M EFI System
/dev/sdc3     1128448    1161215      32768   16M Microsoft reserved
/dev/sdc4     1161216 3905949173 3904787958  1.8T Microsoft basic data
/dev/sdc5  3905949696 3907024895    1075200  525M Windows recovery environment

/dev/sda: My windows boot drive, (which is not being detected)
/dev/sdb: Arch Linux drive
/dev/sdc: An old windows drive, which is now storage. I haven't bothered taking windows off it which I should probably do

When I run os-prober, it recognizes the boot partition from the old disk (/dev/sdc2), but can't find the new one.

I tried installing ntfs-3g, which allowed me to mount the NTFS partition, but even after manually mounting the boot partition, os-prober still couldn't find the boot partition.

I'm fresh out of ideas, so I appreciate your help.
Thanks!

Last edited by clxxiii (2022-12-12 17:56:16)

kermit63

Member

Registered: 2018-07-04

Posts: 225

Re: [SOLVED] os-prober not detecting the windows partition

Try mounting the efi partition of your windows disk instead of the ntfs partition before running os-prober.

I'm assuming that sda1 is some sort of efi partition. If it is not then check if windows is installed in efi or bios mode. If windows in sda is in bios mode, then there is no way for os-prober to detect it if arch is in efi mode.

Last edited by kermit63 (2022-12-12 07:13:43)

clxxiii

Member

Registered: 2022-12-12

Posts: 2

Re: [SOLVED] os-prober not detecting the windows partition

I took a look and it turned out windows was installed in BIOS mode. Thankfully Windows has a pretty good tool to switch it over, I just followed this guide, and everything worked perfectly after that