I'm trying to install Ubuntu. My system have pre-installed Windows 8. I made USB bootable and then I booted into Ubuntu from there and I am in TRY Ubuntu mode now, I am having a problem in installing Ubuntu. When I attempt install Ubuntu then it says:

No root file system is defined. Correct this from the partitioning menu.

  • What do you want to do with the Windows system? Replace it?
    – Lucio
    May 26, 2014 at 21:09
  • No i want both windows and ubuntu to run side by side May 26, 2014 at 21:10
  • Don't you have a "Install Ubuntu alongside Windows" option?
    – Lucio
    May 26, 2014 at 21:11
  • I couldn't find any solution to my problem. can you please brief me a bit. I have set the password for root , now just that how can I define root file and what actually defining a root file means ? May 26, 2014 at 21:22
  • 1
    sorry for duplication, but I was not able to find this. @Fabby, a good link on the problem Mar 3, 2015 at 19:04

1 Answer 1


You need to specify which partition will be root (represented with an slash /) in the partitioning screen. If you don't know how to do this go back twice, and select the automatic installation (the one that doesn't say "Something else...).

To specify the root partition you have to be in the partitioning screen, select the partition where you will install Ubuntu, and then click "Change...". You will be presented with the following:

Thanks to Mateo

Here, in mount point you should select /, click ok, check again everything, and then continue.

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