Help understanding system update warning


For some background to my question, I run two laptops with Manjaro, which I routinely update using sudo pacman -Syu. Two weeks ago, I did what I thought was a normal update on one of them (it didn’t seem as though my internet went down or anything), but when I tried to reboot it was broken. I followed all the regular advice to go in with a USB and reinstall grub via chroot but could not get it working and ended up just recovering my files and reinstalling the whole OS.

Now, I’m trying to be much more careful about updates and really pay attention to the console output & learn the intricacies of the process in better detail. So I’m on the other laptop, and just got this warning during an update:

(16/29) Updating Grub-Bootmenu
Generating grub configuration file ...
Found theme: /usr/share/grub/themes/manjaro/theme.txt
Found linux image: /boot/vmlinuz-5.15-x86_64
Found initrd image: /boot/intel-ucode.img /boot/initramfs-5.15-x86_64.img
Found initrd fallback image: /boot/initramfs-5.15-x86_64-fallback.img
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
Adding boot menu entry for UEFI Firmware Settings ...
Root filesystem isn't btrfs
If you think an error has occurred, please file a bug report at ""
Found memtest86+ image: /boot/memtest86+/memtest.bin
/usr/bin/grub-probe: warning: unknown device type nvme0n1.

I have not rebooted yet. I am not super bootloader savvy yet and I’d really appreciate some help understanding & interpreting this, whether I need to reinstall grub or not, and if it is safe to reboot. Please let me know if there’s any other info/output I can provide to help! Thank you!

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Hi @flutes, and welcome!

Everything looks good from what I can see.

In general, though, a Warning can be safely ignored in a case like this.

Kudos to you for trying to learn. I am also still learning. When you stop learning is when you grow old and you can just as well use the operating system that rhymes with “blows”.


These are normal bla-bla warnings (yes they can be cured but it does not really matter).
BUT it is a very good idea to have one more LTS kernel installed. Right now you have only one.


@Mirdarthos @Teo Thank you!! I’ll look into installing another LTS kernel!

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A warning is a warning. To ‘warn’ you.
This is ‘warning’ that os-prober will be run to check for other systems.
Thats it.

You have grub-btrfs installed instead of grub, so it looks for btrfs filesystem, which you dont have.
This can also be ignored … or you can install grub (replacing grub-btrfs).

there is a toggle for it in /etc/default/grub. If you have a single OS, it will check and find nothing, if you have another OS like dual booting windows it will add it to the boot menu

It is actually installed by default even if you do not have btrfs. At least on the May 23 ISO from which i installed. It can be uninstalled…or just ignored.

I know.
I didnt make any comment on how it got there.
Simply that they have grub-btrfs instead of regular grub while not using btrfs.

Conversely, I believe this is off by default (for most editions), so I might assume they flipped it themselves. Plasma edition for example.

I think it is off by default since about the middle of 2023 and it was on by default earlier. Not that really matters, except for the lost 1 second of execution time :slight_smile: