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I just aquired a new hdd to my windows 7 system and want to install ubuntu 11.10 and grub on it. I have a liveCD but cant make it work. When i chose the new hdd for installation (sdc1) it says "No root file system is defined. Please correct this from the partitioning menu." What should i do to make it work_ this is the first time i try to install ubuntu so i have no previous experience of it.

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up vote 2 down vote accepted

That message basically means that you have not set up the partition to mount the root (i.e. "/"). Please boot from the CD and start installation; assuming the new hard disk, sdc1 is empty, do the following.

1) Choose the option to set up the partition system manually

2) Create your first partition, set the partition type to swap (this will be the swap partition, something like windows page file, you won't see or deal with this partition again but it is necessary for good performance), specify the size (I usually use 4 GB) and create it.

3) Create another partition of type "ext4" (or any other llinux filesystem you wish) and set the size for this one. Where it says to select the mount point, select /

4) (optional) I usually create a separate partition for /home where my files are kept, it is usually a good idea in case you want to do a clean install of ubuntu in future, your data will be on a separate partition. Just create a partition of the desired size and type ext4 and mount point /home

Now install in the partition mounted at / and life is good :)

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I'm trying this at the moment! hope it works. Part 4 seems like a neat idea. – Sergei Feb 10 '12 at 10:11
seems to work perfectly, thank you @kniwor – Sergei Feb 10 '12 at 10:36

The easiest option would be to temporarily unplug the Windows drive, start the installation and then allow Ubuntu "to use the whole drive" or something along those lines - which I believe would be the default option. This, however, would not add Windows to your GRUB boot menu not will it try to migrate your documents and settings from Windows (it.s been a while since I dual-booted with Windows so I may remember this part wrong). You'll be able to add Windows to the GRUB menu manually later or just change boot priority in BIOS setup.

Another option is to partition the drive during the setup manually, which is not difficult at all but is slightly more dangerous than installing with Windows drive unplugged. At the very least, you'll need to create one large ext4 partition for your root filesystem (setting its mount point to /) and another small partition for swap (roughly the size of your RAM).

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