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I disengaged all of my internal hardisks then plugged two things: 1] 4gb Kingston USB made bootable using PowerISO & Ubuntu 12.10 image file. 2] 160gb external WD Scorpio Hardisk

The computer booted normally wth Ubuntu asking wither to try or install. I chose install then proceeded towards manual partitioning.

all as ext4..

/boot 300mb primary (sdb/1)

swap 2000mb primary

/ 17000mb logical

/home 9000mb logical

/opt 14000mb logical

rest free space...

chose sdb/1 as boot point [sda corresponds to USB] proceeded...installation ran then nasty error didnt allow me to proceed, tried different configurations of partition but to no avail error:

Attempt to mount a filesystem with type ext4 ... at '/' failed

plz help me

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Any reason for choosing sdb/1 rather than just sdb. – Hashken Dec 10 '12 at 18:34
bcz it was /boot ...anyways i hav tried otherwise not creating any /boot & choosing just the device as u said but same. – nightcrawler Dec 10 '12 at 18:35
Did you have the format box ticked? – psusi Dec 10 '12 at 18:43
Please confirm if you did this exactly. Just created partitions for /, /home, /opt and not /boot. Chose sdb as location for installing boot loader, where sdb points to your external hard disk. – Hashken Dec 10 '12 at 19:06
Yes I have formatted & also have tried without /boot configuration & now it seems I have found the 'real' bug causing this...though the problem isn't resolved. Before I ask a new question can you tell me that an external drive (via usb) support multiple partitions? I mean can usb external hardisk (in my case WD inside Samsung pocket holder) can have multiple partitions & I think Ubuntu doesn't support it! – nightcrawler Dec 10 '12 at 23:59

Following is step by step for installing 12.04 on a 64GB flash drive on an Intel machine. 12.10 is almost the same. This is just like doing a normal install to internal drive except for the option of making the first partition FAT32 (or leaving it NTFS) so Windows can see it.

Turn off and unplug the computer. (See note at bottom) Remove the side from the case. Unplug the power cable from the hard drive. Plug the computer back in. Insert the flash drive. Insert the Live CD or Live USB. Start the computer, the CD/USB should boot. Select language Select install Ubuntu. Select Download updates while installing and Select Install this third-party software. Continue.

At "Installation type" select "Something else". Continue Confirm Device is correct.

Select "New Partition Table". Click Continue on the drop down.

(Optional partition for use on Windows machine) Click "Free space" and "Add". Make "Size:" about 66000 MB. Select "Primary". Location for the new partition = "Beginning of this space". "Use as:" = "FAT32 file system". And Mount point = "/windows". Select "OK"

Click "free space" and then "Add". Select "Size:" = 4000 to 6000 megabytes, "Primary", Beginning of this space, Ext4, and Mount point = "/" then OK.

(Optional home partition) Click "free space" and then "Add". Select "Size ..." = 1000 to 4000 MB, "Primary", Beginning, Ext2, and Mount point = "/home" then OK.

(Optional swap space, allows hybernation) Click "free space" and then "Add". Select "Primary", "New partition size ..." = remaining space, (1000 to 2000 megabytes, or same size as RAM), Beginning and "Use as" = "swap area" then OK.

(Important) Confirm "Device for boot loader installation" points to the USB drive. Default should be ok if HDD was unplugged.

Click "Install Now". Select your location. Continue. Select Keyboard layout. Continue. Insert your name, username, password, computer name and select if you want to log in automatically or require a password. Selecting "Encrypt my home folder" is a good option if you are worried about loosing your USB drive. Select Continue.

Wait until install is complete. Turn off computer and plug in the HDD. Stick the side panel back on.

Note: You may omit disabling the hard drive if, when partitioning you choose to install grub to the root of the usb drive you are installing Ubuntu to, (ie sdb not sdb1). Be cautious, many people have overwritten the HDD MBR. You can update grub later, if you wish.

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I have done similar steps but weirdness is the final result! I am installing on a 160gb hard I a Samsung enclosure... After installing Ubuntu I boot from my external hard the first time & it runs perfectly. Then I issue the command to shut Ubuntu down, I keep waiting but computer doesn't shut down & thus I manually unplug my CPU. After that first shutdown my external hard never boots with Ubuntu issuing error of unknown filesystem grub rescue – nightcrawler Dec 12 '12 at 14:40

You should have told us earlier about the dirty/improper shutdown. There is a significant chance your ext4 filesystem was corrupted when you yanked the power. Boot a live asession and run fsck on the filesystem to see if the issue is repaired. Also run smartclt -A on the drive (from smartmontools) to make sure there isn't an underlying hardware issue as well.

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