Dual Boot - How to Efficiently Partition a Single Windows-Ubuntu Dual Boot Disk

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This is not a question on how to install Ubuntu or how to use manual partitioning during installation but is a question on access rights and how not to let them bite you in the lower abdomen… 😉

This question will not help you how to make partitions on your disk, but will tell you what to do in step 4 of the installation process, depending on your personal use case, so choose one of the following:

Note: The above questions can also be used with multiple disks, but the examples in the answers are given for one disk.

Best Answer

I know Windows well but Ubuntu not so well

(or the other way around)

Both Windows and Ubuntu are POSIX compliant operating systems and they both allow you to define which user has access to which individual file, directory, partition or disk!

But they do it just a little bit differently (There are full-time jobs for people who have to clean up wrong ownership of data all day long!)

So take the average hard disk:

Windows Installed

If you have more then 1 partition, you're probably running an UEFI system. Please, do not delete any of those partitions! Concentrate on the biggest partition you have and use that one in the following exercise...

Depending on your use case give each OS enough space for its own system and applications (the below numbers are the minimum and recommended system requirements, so you should multiply them by a factor that is comfortable for your use case)

Note: Ubuntu also needs a swap partition of a size described here.

The rest of the disk (-10%) can be given to a data partition formatted to NTFS from gparted See note below so that you arrive at the following lay-out:

Partitioning - Medium


  • Install Windows
  • Create all your users under Windows
  • Install Ubuntu
  • Create all your users under Ubuntu giving them both the same name and the same password as under Windows.
  • Boot the Ubuntu Live CD again and run gparted and shrink both Windows and Ubuntu partitions until they take twice to thrice the amount of the pale yellow bar. Then create the data partition and format it to "ntfs"
  • mount this partition in your fstab (E.g. /media/data)

The following steps credit to:user68186, copied from here

  • Move your data directories to the /Data mount point by pressing Ctrl+Alt+T and copy-paste each line followed by Enter (replace "UserName" by your user name):

      md /media/data/UserName
      md /media/data/UserName/{bin,Desktop,Documents,Downloads,Music,Pictures,Public,Templates,Videos}
      mv /home/UserName/bin /media/data/UserName/bin
      mv /home/UserName/Desktop /media/data/UserName/Desktop
      mv /home/UserName/Documents /media/data/UserName/Documents
      mv /home/UserName/Downloads /media/data/UserName/Downloads
      mv /home/UserName/Music /media/data/UserName/Music
      mv /home/UserName/Pictures /media/data/UserName/Pictures
      mv /home/UserName/Public /media/data/UserName/Public
      mv /home/UserName/Templates /media/data/UserName/Templates
      mv /home/UserName/Videos /media/data/UserName/Videos
  • Make symbolic links for your user to the above directories somewhere else

      ln -s /media/data/UserName/bin/ bin
      ln -s /media/data/UserName/Desktop/ Desktop
      ln -s /media/data/UserName/Documents/ Documents
      ln -s /media/data/UserName/Downloads/ Downloads
      ln -s /media/data/UserName/Music/ Music
      ln -s /media/data/UserName/Pictures/ Pictures 
      ln -s /media/data/UserName/Public/ Public 
      ln -s /media/data/UserName/Templates/ Templates 
      ln -s /media/data/UserName/Videos/ Videos
  • Go to Windows again and move the user directories to your D: drive in the users directory.


When you boot into Windows (or Ubuntu), both Windows and Ubuntu have their own system files and applications installed in their own environment. On top of that, you don't have to worry about which file goes where: All Ubuntu files can be found under Windows in the d:\home directory and all your Windows files can be found under the /users directory in Ubuntu.

If you use any of the following:

  • Ubuntu commands: chown, chmod or Windows command: cacls,
  • if you use any of the file managers to right-click on directories or files to use set permissions

then please do not set permissions from inside Windows in the D:\home nor from inside Ubuntu on the /Users directory ever! Also, do not move files between /users and /home (or D:\home and D:\Users) ever! ###Only copy files!

(and then delete the original because moving will try to move the permissions from one totally different file system to another and that'll give you troubles you want to avoid)

Why is there 10% unallocated space on your drive? Well, that's a little trick when your PC is brand new: you don't need all that space, and that free space is your proverbial spare tire if you ever need to extend one of the other partitions when they run flat! ;-)

Now go back to step 5 of the How to Install Ubuntu and continue there...

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