I have a dual boot system (Ubuntu 18.04 & Windows 10) with 4 primary partitions - the system reserved partition (boot), the windows partition, the ubuntu partition (has /boot, /root, /home, etc) and the swap partition for ubuntu. I want to create another partition (for sharing between windows and ubuntu) and so I need to convert the ubuntu and swap partitions into logical partitions. I did that using fixparts (using this), but on rebooting, I got the grub rescue prompt. While I was able to recover by booting into a live CD and changing the partitions back into primary partitions, I would still like to change the partitions into logical partitions and still have a working system.

What do I need to do here?

Edit 1: More info on UUID

Yes, when I convert the partitions to logical, the UUID does change. After edits with fixparts, when I reload gparted to view the partition information, I don't get an UUID for the partitions at all. I also get this error when I try to get additional information on the partitions:

for /dev/sda5 (the erstwhile primary partition with Ubuntu root, boot etc):

e2label: No such file or directory while trying to open /dev/sda5
Couldn't find valid filesystem superblock.
tune2fs 1.44.1 (24-Mar-2018)
tune2fs: No such file or directory while trying to open /dev/sda5
Couldn't find valid filesystem superblock.
Couldn't find valid filesystem superblock.
dumpe2fs 1.44.1 (24-Mar-2018)
dumpe2fs: No such file or directory while trying to open /dev/sda5
Unable to read the contents of this file system!
Because of this some operations may be unavailable.
The cause might be a missing software package.
The following list of software packages is required for ext4 file system support:  e2fsprogs v1.41+.

Edit 2: From here: "Note that the /boot directory must be located on a filesystem that is supported by GRUB. Not all filesystems are. The function of stage 1.5 is to begin execution with the filesystem drivers necessary to locate the stage 2 files in the /boot filesystem and load the needed drivers. This means that stage 2 of GRUB2 can be located on a standard EXT filesystem but it cannot be located on a logical volume. So the standard location for the stage 2 files is in the /boot filesystem, specifically /boot/grub2."

This seems to imply that I can't convert to logical partition for /boot?

  • 2
    Did the conversion change the UUID? If so, you may need have needed to reinstall all of grub, so it creates new grub menu and edit fstab with new UUID. I would perhaps just changed swap. You can delete it and delete fstab entry that mounts swap. Then create new extended partition and add swap and shared NTFS. Add new swap using new UUID. Make sure Windows 10 fast start up is off as it sets hibernation flag on all NTFS partitions preventing full use from Ubuntu. – oldfred Oct 31 '18 at 16:31

Grub needs some files in /boot folder of your Linux partition. If you change this partition from primary to logical, you have to reinstall Grub to it find them again. You can use boot-repair or do it manually: https://howtoubuntu.org/how-to-repair-restore-reinstall-grub-2-with-a-ubuntu-live-cd

  • Is there a way to backup/restore my grub config before I do this? So that in case things go wrong, I can back out? – Rohith Nov 1 '18 at 12:03

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.