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I have a Ubuntu (actually, Kubuntu) 14.04/

I tried using Gparted Live to resize sda2 and it gave an error, without giving other details (details.html had no information)

Since then, whenever I boot, I get the error 

Error: unknown filesystem.
grub rescue>

I have downloaded BootRepair, and followed the instructions (purge etc) but at the end I still get "unknown filsystem" in the middle of the messages

in grub, I get:

grubrescue> ls
(hd0) (hd0, gpt3) (hd0, gpt2)  (hd0, gpt1)  (hd1)
grubrescue> ls (hd0,2)\
error: unknown filesystem

also,:

grubrescue> set root=(hd0,2)
grubrescue> set prefix=(hd0,2)/boot/grub
grubrescue> insmod normal
error: unknown filesystem

This is the boot-repair info: http://paste.ubuntu.com/22179649

Kanaka
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1 Answers1

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It appears that there is a mixture of efi and MBR booting this is supported but it is very complicated to set up. If you have no valuable information on the disk I would recommend a complete reinstall of you OS after you have recreated the disk partition table and reformatted the partitions. Obviously you will lose all info currently on the disk. If you wish to recover the info then you can attempt to repair the portion table by other means. This is not a trivial task and should not be undertaken lightly. If you wish to pursue this route then I would recommend a considerable amount of research prior to attempting any repair. It is very easy to make matters worse. A good starting place is Rods Books on EFI and GPT. There are a number of excellent articles on these topics with instructions and help in implementing both. You have probably tried to use an MBR type repartitioning tool on a hot portioned disk. Usually this fails without causing damage as the GPT spec has provision for a protective MBR. I do not know what the boot repair tool did but it seems to have made matters worse. Before you start to reinstall decide if you want to use GPT or MBR disk partitions and then use appropriate tools. Also you should decide on the type of booting you are using. (EFI or MBR). By the way is there a particular reason to use Ubuntu 14.04. If not then I recommend using 16.04 the latest LTS release. Hope this gives you some pointers and goes some way to help you.

OldJim
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  • Hot portioned disk is a typo for GPT partitioned! – OldJim Aug 04 '16 at 16:39
  • Oh me! Thanks for the in-depth response. You really gave me to think!

    While there is a lot of important stuff on the disk, I guess there's nothing I can't backup and re-restore after.

    It's just a lot of software to re-configure etc.

    thanks again

     – Kanaka Aug 04 '16 at 16:43
  • Good luck with the backup. The partition table corruption may cause this to fail but it is certainly worth trying. It will not do any harm. – OldJim Aug 04 '16 at 17:25
  • I only see gpt partitioning with the protective MBR. Have you tried fsck on Linux partition from live installer? http://askubuntu.com/questions/642504/ubuntu-14-04-is-not-booting-normaly-after-a-manual-hard-boot/642789#642789 – oldfred Aug 04 '16 at 17:31
  • There's no evidence of dual-mode (EFI/BIOS) booting, except that /dev/sdb, which is presumably the emergency boot medium, has a BIOS-mode boot loader. The /dev/sda hard disk is GPT, has an EFI-mode boot loader, and shows no evidence of any BIOS-mode boot loader. I agree with oldfred that doing an fsck on /dev/sda2 may be worth trying. – Rod Smith Aug 05 '16 at 17:20