EDIT2: This issue seems to have been fixed in 11.04, when installing it now has an option called 'install Ubuntu alongside X' where X is your other operating system. This was very helpful for newbies like me who don't want to play with hard drive partitions.

I would like to install Ubuntu on my laptop as my primary operating system while keeping Windows. When I get to the screen that says "Allocate Disk Space," I click specify partitions manually because I don't want to erase Windows.

Problem is, I don't know how to specify partitions manually. It's all one huge green bar called sda1 (ntfs). What do I do next?

If I press install now, it says no root files system is defined. I tried the "shrink volume" function in Windows, but it complained telling me to run chkdsk, so I right clicked the c drive and nagivated to the chkdsk utility, told it to run on the next startup, which it didn't.

I am running Windows 7.

EDIT: I figured it out, see answer below

  • Also, according my defrag software all the windows stuff is all at the beginning of the drive with a few files at the end. Is there really a significant speed boost that can be obtained by placing files at the beginning of the drive (so the RW head doesn't need to move as far) – jeffythedragonslayer Apr 28 '11 at 1:14
  • well yes.. since it would start looking for files..at the beginning instead of the end – Uri Herrera Apr 28 '11 at 1:16

What Windows version are you running? I assume Vista or 7?

You should really do a chkdsk before messing with the volume. Press Start, type cmd. Click with the right mousebutton on the found cmd.exe and choose "Run as administrator".

Now type "chkdsk c: /f" (without quotes) and press enter.

Now, it'll ask "Chkdsk cannot run because the volume is in use [...] next time the system restarts? (Y/N)". Answer Yes. Now reboot into Windows again to have the disk checked and fixed if needed.

After this is done, AND you have made backups of your valueable data, you can boot into Ubuntu again. When booted into the desktop environment, start 'gparted' to get a nice partition manager to shrink the Windows partition. When that is done, you can Install Ubuntu hopefully without any problem.

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What you need to do is run chkdsk manually during bootup. Spam F8 during bootup, select the repair option and start a command prompt window. Then type chkdsk c: /f to fix the volume.

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If an NTFS partition is shrunk, Windows will run chkdsk on the next reboot. At least it always has done so in the past for me. It's very important that this is done.

I'm assuming that you've already shrunk your Windows partition from inside Windows using the Windows utility. If you haven't done so you should do so now. It's always a good idea to first defragment the drive before you shrink an NTFS partition.

OK, so now you have some extra space where you're going to install Ubuntu. Pop the installation CD in the drive and when you get to the partitioning stage you'll now see the green ntfs Windows partition, but also a bar of unallocated space.

Choose the manual method.

I don't know how much unallocated space you have but ideally you now want to put three partitions in that unallocated space. These will be:

  • / [root file system] - format as ext4 - (10-15 GB should suffice)
  • swap [Windows uses a swap file, but generally Ubuntu dedicates its own partition] - format as swap - (4 GB should be enough. Some advocate 1.5 x the amount of RAM you have but I've always found 4 GB to be plenty)
  • /home [Ubuntu's version of My Documents] - format as ext4 - (all the rest of the space you have left on the hard drive)

The installer will ask you to check and confirm you want to make these changes. The important thing is that the ntfs partition isn't reformatted as that will nuke your Windows install.

Later in the process you will be asked where to install the boot loader (Grub2). Choose to put this in the MBR. Note that you'll still be able to boot Windows in the future but now you'll have a menu (Grub2) at boot up time to choose between Ubuntu or Windows.

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