Grub rescue in windows 7

hi, I'm using acer aspire E1-431 Windows 7, I tried to resize my partitions, after that while re starting I could see this error "unknown file system", also entering rescue mode, I tried to recover this problem by browsing but I could't solve this, every of recovering methods are being related to ubuntu, I have zero knowledge about ubuntu, also i don't have CD/DVD port, please help me to boot my system….

Hi Maseelan Rajan, and welcome to the WTT forums.

Sorry to hear about the problem with your computer.

My data sheets indicate that the Acer Aspire E 1-431 comes equipped with a DVD drive….. is yours missing? or is it a special model that does not have one?

If you find there is a DVD drive then use your Windows Recovery disc Or Windows 7 installation disc to boot  your machine and perform a complete factory restore (remember this will destroy all your files so do check that your back up files are comprehensive, accurate, up to date, and include everything important to you , before you start . you should also have at least one extra copy of all your back ups (and any disc images made when the computer was running fast and sweet) kept safe on removable media offsite.

If you don't have a DVD drive installed in your computer or its not working then borrow an external USB hard drive from a chum (they are not expensive to buy,,. around GBP £20 or so) and use that (you may need to alter the BIOS so you can boot from DVD drive or external USB device)  You could also boot from a USB key that has Win 7 on it…post back if you need further help with any of this.

I don't understand your reference to Ubuntu…did this computer have Ubuntu installed on it?

Were you using a Grub loader for dual or triple boot?

Have you formatted any part of your drives using a Linux file system or using a Linux Ubuntu tool/software?

What tool or software were you trying to use to resize your partitions and why?

Regards

paws

sounds to me like he's installed ubuntu and overwritten the mbr so the only way he's going to get windows 7 back if he hasn't wiped the recovery partition and doesn't have a win7 disc is to use a live cd and to make the recovery partition the boot partition using something like fdisk then restart his laptop that should start the recovery process so he can do a full factory restore.

if the mbr is fine then this link will show him how to restore to factory using the hidden partition :- http://acer.custhelp.com/app/answers/detail/a_id/2631

how to use fdisk and toggle boot partition flag.

 

6. Toggle the Boot Flag of a Partition Using fdisk Command a

Fdisk command displays the boot flag of each partition. When you want to disable or enable the boot flag on the corresponding partition, do the following.

If you don’t know why are you are doing this, you’ll mess-up your system.

# fdisk /dev/sda

The number of cylinders for this disk is set to 9729.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)                               

Command (m for help): p

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xf6edf6ed

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1        1959    15735636    c  W95 FAT32 (LBA)
/dev/sda2            1960        5283    26700030    f  W95 Ext'd (LBA)
/dev/sda3            5284        6528    10000462+   7  HPFS/NTFS
/dev/sda4            6529        9729    25712032+   c  W95 FAT32 (LBA)
/dev/sda5   *        1960        2661     5638752   83  Linux
/dev/sda6            3265        5283    16217586    b  W95 FAT32
/dev/sda7            2662        3264     4843566   83  Linux

Partition table entries are not in disk order

Command (m for help): a
Partition number (1-7): 5

Command (m for help): p

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xf6edf6ed

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1        1959    15735636    c  W95 FAT32 (LBA)
/dev/sda2            1960        5283    26700030    f  W95 Ext'd (LBA)
/dev/sda3            5284        6528    10000462+   7  HPFS/NTFS
/dev/sda4            6529        9729    25712032+   c  W95 FAT32 (LBA)
/dev/sda5            1960        2661     5638752   83  Linux
/dev/sda6            3265        5283    16217586    b  W95 FAT32
/dev/sda7            2662        3264     4843566   83  Linux

Partition table entries are not in disk order

Command (m for help):

As seen above, the boot flag is disabled on the partition /dev/sda5.

http://www.thegeekstuff.com/2010/09/linux-fdisk/

if your not sure what your doing just do a fdisk -l command and post the results back here so we can see what partitions are on the hard drive and advise you further.

I reckon you are right Terry (as usual!)

Its great we have you as our own Linux Guru here on WTT

Regards

paws

I'm sorry to say this, because it's not working still, I'm new for this issue, while I enter fdisk command it shows unknown command,

I was messed with Ubuntu, here I clearly explain, I did't use that ubuntu os before, in youtube i saw recovery solution using ubuntu that's why I messed with that, it's linux with windows 7 only

Actually cause for this problem is,

in 'my computer' right click i saw a option 'manage', after that I realize  93gb did't partitioned in my hard disk, so simply try to partition, later I restart it displays

"GRUB loading.

  Welcome to GRUB!

  error: unknown filesystem.

  Entering rescue mode…

  grub rescue>  _"

this what is my problem… 

before that Thank you for reply for my question..

I'm looking forward to see your next reply, thank you…

my system has BOSS(Bharat Operating System Solutions) linux

(

) india based OS, with windows 7, hope you can understand my problem…

Here is my problem. I have Windows 7 and Linux Boss installed on to my laptop. My computer's hard disk size is 320 GB. When I work on Windows, i found 100 GB is unoccupied and therefore i went for partition and added a new local disk E: . But later I came to know that my Linux OS has that 100 GB of memory. Now, I'm not able to boot in to my system as I'm getting error: unknown filesystem. Entering rescue mode… grub rescue> What am I supposed to do to get back both the OSs?

ok this is what i think is now happening.

the needed grub boot files were on the ubuntu partition and are no longer there because of the windows format you did, (neither is the ubuntu os.) as you now know windows doesn't see linux partitions and says they are empty space. so if you want both os back bootable you will need to re-install the ubuntu os,

i'd really like to see your partition table tho before you make any more changes to the drive so please try again with a linux live cd, fdisk needs root access so the full command you need to use with ubuntu live cd i'd guess is

sudo fdisk -l

we may be able to get things working again without the need of a re-install of ubuntu using grub rescue, but not 100% sure it will work and i will need to see the partition table before giving you the commands to use.

Wouldn't running Startup Repair up to 3 times from the Windows 7 install DVD fix this?

not if you wanted the ubuntu os to work.

would fix the boot problem for the windows 7 os tho i'd expect.

I mentioned early, system does't contain CD/DVD drive, it's okay.., now i'm trying to download same BOSS 4.1 from boss website itself, after that I can convert that into flash drive, hope this will work with your help..

I also need this information, is linux(boss) necessary to boot Windows 7, If not give any suggestion to recover windows 7 only..

thank you….

without the needed partition table i can not give exact instructions, but try this when you start your pc and are at the grub rescue pronpt.

X is going to be a number but i don't know that number because you haven't supplied the needed info.

so try numbers from 1 to 7 where it says X, probably 4 or 5 is going to be the correct number/partition.

hit enter after each line

set boot=(hd0,X) 

set prefix=(hd0,X)/boot/grub

insmod normal

normal

 if this never worked then you're going to have to do a reinstall of boss, this will then add the windows os to it's boot loader so you can boot both os again,

if it worked and you got the boot menu and can now boot into boss or win7 then you will need to boot into boss and install grub with these commands to make it a permanent fix.

sudo grub-update

sudo grub-install /dev/sda 

now.

 

I also need this information, is linux(boss) necessary to boot Windows 7, If not give any suggestion to recover windows 7 only..

no linux is not needed to boot into win7.

you have a number of options here mentioned in earlier posts by both paws and ztruker.

1:-

 

running Startup Repair up to 3 times from the Windows 7 install DVD fix this?

http://windows.microsoft.com/en-GB/windows7/products/features/startup-repair

another link that shows how to fix the boot problem.

http://www.tomshardware.com/news/win7-windows-7-mbr,10036.html

2:- you can use a live cd and fdisk to change the boot (active) partition so it boots into win7 on a restart and fix the mbr from there.

3:- make the recovery partition the boot partition with fdisk and on a restart you will have the option to restore to factory state, this of course will loose all your data and installed programs from new.

It's not working, also I don't want to lose my data, so I'm downloading BOSS os now, may be a upgrade OS than my lost version…

thank you for being with me to solve this issue….

ok it probably didn't work because win7 zero'd the partition when it formatted it, i do believe this is now default with the newer windows os where before it just used to do a quick format leaving the data still there on the rest of the partition.

please be careful when doing a reinstall and make sure you install it to the same partition it was first on, also if you did the windows startup repair so just the win7 os worked again you wouldn't lose any of your win7 data.

i'd still like to see your partition table BEFORE you made any changes to the hard drive like installing boss again, just to clarify a few things in my mind please.

How can I retrieve my partition table, because fdisk command is not working in this grub rescue pronpt,

this what is happen while I giving fdisk  or sudo fdisk command

error: unknown filesystem.

Entering rescue mode…

grub rescue> fdisk -l

Unknown command 'fdisk'

grub rescue>

but it retrieves partitions while using 'ls' command

grub rescue> ls

(hd0) (hd0,msdos5) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1)

grub rescue>

so, I thought fdisk command is work with the BOSS flash drive, that's I'm downloading boss iso right now.. 

I'm always looking forward to give you the partition table details, hopefully I'll post that soon…