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I had installed windows 8 and ubuntu in my laptop. but after that by mistake i formatted the drive in which ubuntu was installed so now when ever i reboot my machine i get the error: unknown filesystem and grub rescue. I want to reinstall ubuntu again in the same drive but i am unable to install because of grub rescue. please suggest me solution to install ubuntu from grub rescue or to delete grub so that i can reinstall ubuntu in normal way. I am able to boot to windows if i keep the boot mode to UEFI.

marked as duplicate by Braiam, Eric Carvalho, mikewhatever, Alvar, BuZZ-dEE Dec 27 '13 at 10:33

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  • Boot into windows and create a bootable ubuntu usbdrive through unetbootin.

  • Then Change UEFI mode to legacy mode in bios and boot from ubuntu live usb.

  • During the installation process of ubuntu select Something Else option.Now you can install ubuntu in a partition you want.After the installation process completed,your grub will be reinstalled.

  • Now you can see both windows and ubuntu options on the grub menu.If the windows option was not displayed,then boot into ubuntu and run sudo update-grub command on terminal.

  • Why change to legacy mode? Ubuntu should be installed in UEFI mode if Windows is also booting this way. Reinstalling (in UEFI mode) as you described should work and reinstall the (UEFI) bootloader. There are probably more than one UEFI boot entries that point to wrong configurations (UUIDs). Best way would be to delete all existing Ubuntu entries before reinstalling. See: askubuntu.com/questions/63610/… – LiveWireBT Dec 25 '13 at 9:16

I guess this is related to having more than one UEFI bootmenu entry for Ubuntu and the wrong one is picked leading to GRUB not being able to proceed (wrong UUID for the partition where GRUB is stored?).

I suggest booting from live media in UEFI mode and removing the faulty Ubuntu bootmenu entries (e.g. all Ubuntu entries) before attempting to reinstall via the installer option "Something else".

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