Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

My situation is the following

I have no Linux experience. I have a hard disk with two partitions. One used to have Windows 7 on it, the other one was recently formatted in preparation for an Ubuntu install.

I made an Ubuntu live CD and tried to install it to the empty partition. I also took the opportunity to format the Windows partition in preparation for reinstalling Windows 7 afterwards.

The Ubuntu installation reported a fatal grub error and also tells me that the bootloader could not be installed.

When trying to install Windows 7, the installation now also fails due to some nondescript partitioning related error.

My computer has effectively become unusable. Thankfully liveCD lets me try out Ubuntu.

I have used the GParted partition editor to wipe the drive clean. How should I set up the partitions so that I can properly install both OS?

Once this is done, how do I fix the grub/bootloader problem?

share|improve this question
Important information for us in order to be able to help: Does your computer use UEFI or is it still using BIOS? – soulsource Jul 24 '13 at 12:35
My computer uses UEFI – MarkT Jul 24 '13 at 12:39

Since your PC uses UEFI, the starting point I'd recommend is the official Ubuntu UEFI guide. Another source of information is the question regarding Windows 8/Ubuntu Dual Boot with UEFI.

The main statement of these articles is, that both, Windows and Ubuntu have to be installed using the same firmware interface. This means, if you install Windows using UEFI mode (only possible with the 64bit version of Windows 7), you have to use the 64bit version of Ubuntu and boot the installer using UEFI mode. Usually, the 64bit Ubuntu CD/USB-Drive is shown twice in the boot device selection, once with UEFI, once without, the same for a 64bit Windows DVD.

Screenshot of a boot device selection showing UEFI options

For your specific question: I'd start out by creating a new partition table (warning: backup stuff first!) on the HDD you are going to use (for instance using gparted). If you are going to use UEFI, you have to create a GPT partition table. If you plan on using BIOS mode, the partition table has to be MBR. You don't need to create partitions yet (I'd use the Windows installer to make the Windows partitions and just leave enough space for Ubuntu unpartitioned).

Another thing with UEFI is, that Ubuntu still has some issues with certain firmwares and therefore bootloader installation might fail on some mainboards. In such a case, I'd try to use the latest Ubuntu version and to update the firmware. If this does not help, you have to use BIOS emulation...

If you have a 64bit Windows 7, my suggestion would be:

  • Create a new, empty GPT partition table on the HDD with gparted
  • Install Windows 7 in UEFI mode, leaving some space unpartitioned for Ubuntu (I'd say: more than 10 GB)
  • Install Ubuntu 64bit in UEFI mode.

If this works, you're fine.

If not, or if your Windows 7 is 32bit, then you'll probably have to use BIOS emulation.

  • Again, create a new, empty partition table with gparted, in this case MBR.
  • For Windows Installation, boot the Windows DVD in BIOS/Legacy mode (see the Ubuntu UEFI guide for more details - if required, disable UEFI booting completely)
  • Install Ubuntu in BIOS mode (by either using the 32bit Ubuntu, or by booting from the 64bit Ubuntu DVD in Legacy/BIOS mode.
share|improve this answer

Just because your motherboard has UEFI, your Windows may not have been installed in UEFI mode? Most Windows 7 systems used CSM/BIOS/Legacy mode, only a few new systems released just before Windows 8 seemed to use UEFI with Windows 7. But many systems with Intel i-series chips had UEFI/BIOS motherboards.

Do you remember if you had an efi partition or a 100MB Boot partition used with BIOS boot mode.

You may need to either erase all gpt data to make drive MBR, you can use fixparts. FixParts is the easiest way to remove the stray GPT data. GPT fdisk (gdisk or sgdisk) can do it, but the procedure's a bit more involved.

And if installing in BIOS mode, you need a primary partition (sda1 thru sda4), formatted NTFS with the boot flag. Some using gparted to create NTFS have had to reformat with Windows 7 and recreate active partition (boot flag).

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.