I know the question has been asked so many times but in my case whatever I do as indicated in the following post (all solutions are tried) 'unknown filesystem' is the ultimate reply..
Grub rescue – error: unknown filesystem
I also tried live USB of boot-disk-recovery which too fails to identify my device partition holding Ubuntu 12.04 x32 (which by the way is sdb2) Although it created bootscript which is attached below.
Boot Info Script e7fc706 + Boot-Repair extra info [Boot-Info 31Jan2013]
============================= Boot Info Summary: ===============================
=> Syslinux MBR (4.04 and higher) is installed in the MBR of /dev/sda.
=> Grub2 (v1.99) is installed in the MBR of /dev/sdb and looks at sector 1 of
the same hard drive for core.img. core.img is at this location and looks
for (,msdos2)/boot/grub on this drive.
sda1: __________________________________________________________________________
File system: vfat
Boot sector type: SYSLINUX 4.05 20120702
Boot sector info: Syslinux looks at sector 1030576 of /dev/sda1 for its
second stage. SYSLINUX is installed in the directory.
According to the info in the boot sector, sda1 starts
at sector 0. But according to the info from fdisk,
sda1 starts at sector 62.
Operating System:
Boot files: /syslinux/syslinux.cfg /ldlinux.sys
sdb1: __________________________________________________________________________
File system: swap
Boot sector type: -
Boot sector info:
sdb2: __________________________________________________________________________
File system:
Boot sector type: -
Boot sector info:
Mounting failed: mount: unknown filesystem type ''
sdb3: __________________________________________________________________________
File system: Extended Partition
Boot sector type: Unknown
Boot sector info:
sdb5: __________________________________________________________________________
File system:
Boot sector type: Windows Vista: NTFS
Boot sector info:
Mounting failed: mount: unknown filesystem type ''
mount: unknown filesystem type ''
============================ Drive/Partition Info: =============================
Drive: sda _____________________________________________________________________
Disk /dev/sda: 4003 MB, 4003463168 bytes
124 heads, 62 sectors/track, 1017 cylinders, total 7819264 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
Partition Boot Start Sector End Sector # of Sectors Id System
/dev/sda1 * 62 7,818,695 7,818,634 c W95 FAT32 (LBA)
Drive: sdb _____________________________________________________________________
Disk /dev/sdb: 80.0 GB, 80026360832 bytes
255 heads, 63 sectors/track, 9729 cylinders, total 156301486 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
Partition Boot Start Sector End Sector # of Sectors Id System
/dev/sdb1 2,048 2,000,895 1,998,848 82 Linux swap / Solaris
/dev/sdb2 * 2,000,896 58,644,479 56,643,584 83 Linux
/dev/sdb3 58,646,526 156,301,311 97,654,786 5 Extended
/dev/sdb5 58,646,528 156,301,311 97,654,784 7 NTFS / exFAT / HPFS
"blkid" output: ________________________________________________________________
Device UUID TYPE LABEL
/dev/loop0 squashfs
/dev/sda1 3273-D2BD vfat
/dev/sdb1 19d35932-1dbf-4be0-83aa-3d76b646dd80 swap
================================ Mount points: =================================
Device Mount_Point Type Options
/dev/loop0 /rofs squashfs (ro,noatime)
/dev/sda1 /cdrom vfat (ro,noatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
========================= sda1/syslinux/syslinux.cfg: ==========================
--------------------------------------------------------------------------------
# D-I config version 2.0
include menu.cfg
default vesamenu.c32
prompt 0
timeout 300
ui gfxboot bootlogo
--------------------------------------------------------------------------------
================= sda1: Location of files loaded by Syslinux: ==================
GiB - GB File Fragment(s)
?? = ?? syslinux/syslinux.cfg 1
?? = ?? ldlinux.sys 1
?? = ?? syslinux/chain.c32 1
?? = ?? syslinux/gfxboot.c32 1
?? = ?? syslinux/vesamenu.c32 1
============== sda1: Version of COM32(R) files used by Syslinux: ===============
syslinux/chain.c32 : COM32R module (v4.xx)
syslinux/gfxboot.c32 : COM32R module (v4.xx)
syslinux/vesamenu.c32 : COM32R module (v4.xx)
======================== Unknown MBRs/Boot Sectors/etc: ========================
Unknown BootLoader on sdb3
00000000 d6 d6 d6 d6 d6 d6 d6 d6 d6 d6 d6 d6 d6 d6 d6 d6 |................|
*
000001b0 d6 d6 d6 d6 d6 d6 d6 d6 d6 d6 d6 d6 d6 d6 00 fe |................|
000001c0 ff ff 07 fe ff ff 02 00 00 00 00 18 d2 05 00 00 |................|
000001d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|
00000200
=============================== StdErr Messages: ===============================
File descriptor 8 (/proc/2401/mounts) leaked on lvscan invocation. Parent PID 7264: bash
No volume groups found
ADDITIONAL INFORMATION :
=================== log of boot-repair 2013-11-26__17h13 ===================
boot-repair version : 3.198~ppa16~raring
boot-sav version : 3.198~ppa16~raring
glade2script version : 3.2.2~ppa45~raring
boot-sav-extra version : 3.198~ppa16~raring
File descriptor 8 (/proc/2401/mounts) leaked on lvs invocation. Parent PID 4002: /bin/sh
No volume groups found
boot-repair is executed in live-session (Boot-Repair-Disk 32bit 24avr2013, raring, Ubuntu, i686)
ls: cannot access /home/usr/.config: No such file or directory
CPU op-mode(s): 32-bit, 64-bit
noprompt cdrom-detect/try-usb=true file=/cdrom/preseed/lubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash --
=================== os-prober:
=================== blkid:
/dev/loop0: TYPE="squashfs"
/dev/sda1: UUID="3273-D2BD" TYPE="vfat"
/dev/sdb1: UUID="19d35932-1dbf-4be0-83aa-3d76b646dd80" TYPE="swap"
=================== UEFI/Legacy mode:
This live-session is not EFI-compatible.
SecureBoot maybe enabled.
=================== PARTITIONS & DISKS:
=================== parted -l:
Model: Kingston DT 101 G2 (scsi)
Disk /dev/sda: 4003MB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number Start End Size Type File system Flags
1 31.7kB 4003MB 4003MB primary fat32 boot, lba
Model: Mass Storage Device (scsi)
Disk /dev/sdb: 80.0GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number Start End Size Type File system Flags
1 1049kB 1024MB 1023MB primary linux-swap(v1)
2 1024MB 30.0GB 29.0GB primary boot
3 30.0GB 80.0GB 50.0GB extended
5 30.0GB 80.0GB 50.0GB logical ntfs
=================== parted -lm:
BYT;
/dev/sda:4003MB:scsi:512:512:msdos:Kingston DT 101 G2;
1:31.7kB:4003MB:4003MB:fat32::boot, lba;
BYT;
/dev/sdb:80.0GB:scsi:512:512:msdos: Mass Storage Device;
1:1049kB:1024MB:1023MB:linux-swap(v1)::;
2:1024MB:30.0GB:29.0GB:::boot;
3:30.0GB:80.0GB:50.0GB:::;
5:30.0GB:80.0GB:50.0GB:ntfs::;
=================== mount:
/cow on / type overlayfs (rw)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
udev on /dev type devtmpfs (rw,mode=0755)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)
tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755)
/dev/sda1 on /cdrom type vfat (ro,noatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
/dev/loop0 on /rofs type squashfs (ro,noatime)
none on /sys/fs/cgroup type tmpfs (rw)
none on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)
none on /sys/kernel/security type securityfs (rw)
tmpfs on /tmp type tmpfs (rw,nosuid,nodev)
none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880)
none on /run/shm type tmpfs (rw,nosuid,nodev)
none on /run/user type tmpfs (rw,noexec,nosuid,nodev,size=104857600,mode=0755)
gvfsd-fuse on /run/user/lubuntu/gvfs type fuse.gvfsd-fuse (rw,nosuid,nodev,user=lubuntu)
=================== ls:
/sys/block/sda (filtered): alignment_offset bdi capability dev device discard_alignment events events_async events_poll_msecs ext_range holders inflight power queue range removable ro sda1 size slaves stat subsystem trace uevent
/sys/block/sdb (filtered): alignment_offset bdi capability dev device discard_alignment events events_async events_poll_msecs ext_range holders inflight power queue range removable ro sdb1 sdb2 sdb3 sdb5 size slaves stat subsystem trace uevent
/dev (filtered): agpgart alarm ashmem autofs binder block bsg btrfs-control bus char console core cpu cpu_dma_latency disk dri ecryptfs fb0 fd full fuse fw0 hidraw0 hidraw1 hidraw2 hpet input kmsg kvm log mapper mcelog mem net network_latency network_throughput null oldmem port ppp psaux ptmx pts random rfkill rtc rtc0 sda sda1 sdb sdb1 sdb2 sdb3 sdb5 sg0 sg1 shm snapshot snd stderr stdin stdout uinput urandom usb v4l vga_arbiter vhost-net video0 zero
ls /dev/mapper: control
=================== df -Th:
Filesystem Type Size Used Avail Use% Mounted on
/cow overlayfs 1.5G 19M 1.5G 2% /
udev devtmpfs 1.5G 12K 1.5G 1% /dev
tmpfs tmpfs 300M 816K 299M 1% /run
/dev/sda1 vfat 3.8G 496M 3.3G 14% /cdrom
/dev/loop0 squashfs 431M 431M 0 100% /rofs
none tmpfs 4.0K 0 4.0K 0% /sys/fs/cgroup
tmpfs tmpfs 1.5G 8.0K 1.5G 1% /tmp
none tmpfs 5.0M 0 5.0M 0% /run/lock
none tmpfs 1.5G 0 1.5G 0% /run/shm
none tmpfs 100M 12K 100M 1% /run/user
=================== fdisk -l:
Disk /dev/sda: 4003 MB, 4003463168 bytes
124 heads, 62 sectors/track, 1017 cylinders, total 7819264 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00011134
Device Boot Start End Blocks Id System
/dev/sda1 * 62 7818695 3909317 c W95 FAT32 (LBA)
Disk /dev/sdb: 80.0 GB, 80026360832 bytes
255 heads, 63 sectors/track, 9729 cylinders, total 156301486 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x7add7add
Device Boot Start End Blocks Id System
/dev/sdb1 2048 2000895 999424 82 Linux swap / Solaris
/dev/sdb2 * 2000896 58644479 28321792 83 Linux
/dev/sdb3 58646526 156301311 48827393 5 Extended
/dev/sdb5 58646528 156301311 48827392 7 HPFS/NTFS/exFAT
Error: no partitions
=================== Default settings
Recommended-Repair
This setting would reinstall the of .
Additional repair would be performed: repair-filesystems
=================== Settings chosen by the user
Boot-Info
This setting will not act on the MBR.
No change has been performed on your computer.
While I attach this sdb (as external) to any running OS following observations were made:
In Linux Mint's gPArted:
Partitions /sdb1 (ext4) & /sdb5 (ntfs) both have exclamation marks! (thus my ntfs too is corrupted somehow)
In Win7
/sdb5 also can't be accessed rather windows offer me to format it to use it. chkdsk can't access this ntfs partition!
I have tested my hd for bad sectors but it's healthy & why it shouldn't be its only ~3 months old. Now I have tried whatever I can for the last 2 days but now you guys I look upon for assistance
UPDATE 1
I have tried fsck.ext4 -v /dev/sdb2 but bad superblock error was returned. Used mke2fs -n /dev/sdb2 to get a list of backup superblocks & finally upon each block number e2fsck -b <block_number> /dev/xxx was performed with no success 🙁
UPDATE 2
Used testdisk utility & performed deep search for lost partitions & then tried to list files upon each found partition some of the NTFS partiton allowed me to enter them but there were no files only "System Volume Information" stuff (some files I put in my /dev/sd5 should be there!). It displayed that hd structure is present but I can't hook up in the Linux partition nether testdisk was able to list files of that particular partition
UPDATE 3
This is the 3rd day & still I can't get it to work so I am writing a prologue of how did my problem really started…This 80gb drive though is my internal PC drive but frequently I also attach this as an external drive to my laptop. The drive was working fine for about 3 months.
Under linux Mint (in my laptop) I attached it 3 days before (& I often do that) as an external USB drive. There I transferred ~16gb of data to its NTFS partition /dev/sdb5. It went smoothly with ~25mb/sec rate & then I (what I do always) issued through context menu 'Safely remove drive' & it removed drive (I think that was what supposed to happen) nothing special! but later when I tried to boot it nightmare started…
After a quick Google search I must acknowledge that Linux may also corrupt your Grub & all even when drive isn't properly unmounted, thats really a shame to find because in windows I just pull out my USBs when transfer finishes but yes in *nix I do have found that even when transfer is completed & you pull out drive only to find nothing has been transferred! Bad luck if you used cut/paste
Best Answer
Several problems:
With no blkids being listed for the partitions, it does not look good for recovery. I suppose you could check the partition with dd, grab a few blocks at a time in locations spread across the partition, and look for strings, to see if the data even exists. But if it's just configuration data, definitely not worth the effort. For more valuable data, if the usual tools don't help, there's always brute force, dd the whole partition, split it up into manageable chunks, look for strings of interest, then edit the chunk with the interesting stuff -- a massive undertaking.