Comment 83 for bug 1274320

I get the same problem. what I also see is, that I get the follow message on update-grub:

# LANG=C update-grub
Generating grub configuration file ...
/usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
/usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
/usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
/usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
Found linux image: /boot/vmlinuz-3.13.0-37-generic
Found initrd image: /boot/initrd.img-3.13.0-37-generic
/usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
/usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
/usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
Found linux image: /boot/vmlinuz-3.13.0-32-generic
Found initrd image: /boot/initrd.img-3.13.0-32-generic
/usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
/usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
/usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
/usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
Found memtest86+ image: /boot/memtest86+.elf
Found memtest86+ image: /boot/memtest86+.bin
done

and when I try to run the abstraction target I also get this:

# grub-probe --target=abstraction "/boot/grub/"
grub-probe: Warnung: Physischer Datenträger »(null)« konnte nicht gefunden werden. Einige Module könnten im Core-Abbild fehlen..
diskfilter
mdraid1x

but not when I run the disk/fs target - so this seems more stable to me?!

# grub-probe --target=disk "/boot/grub/"
/dev/md0

# grub-probe --target=fs "/boot/grub/"
ext2

# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.1 LTS
Release: 14.04
Codename: trusty

# dpkg -l|grep grub
ii grub-common 2.02~beta2-9ubuntu1 amd64 GRand Unified Bootloader (common files)
ii grub-gfxpayload-lists 0.6 amd64 GRUB gfxpayload blacklist
ii grub-pc 2.02~beta2-9ubuntu1 amd64 GRand Unified Bootloader, version 2 (PC/BIOS version)
ii grub-pc-bin 2.02~beta2-9ubuntu1 amd64 GRand Unified Bootloader, version 2 (PC/BIOS binaries)
ii grub2-common 2.02~beta2-9ubuntu1 amd64 GRand Unified Bootloader (common files for version 2)