I am going to install Ubuntu on a brand new PC, which comes with some OEM installation of Windows 7. I know that Ubuntu can resize an existing Windows NTFS partition, so that it has free space to install. However, I am not sure how safe it is, and I'd like opinions, and tips'n'tricks on what I can do to avoid problems. The PC does not contain any data and I will have the recovery disk.


  • I have done this recently and experienced no problems. As stated below a safe way is to resize the windows partition first. I was not able to install the 10.10 version, but the 10.04 version worked fine. I think this is a hardware issue though and should not concern you if you do not have a raid system
    – Martin H
    Dec 14, 2010 at 16:35

7 Answers 7


If there's data you can't stand to lose (ie that couldn't be recovered by just reinstalling) it doesn't matter if you're repartitioning or not, back it all up to an external drive.

Resizing NTFS is a pretty tried and tested technology (it has been one of the main install vectors for people trying Linux in the past, and probably still is) so you should be fairly confident you won't rinse your drive when you do it. It's had a lot of attention and there are a lot of tools out there to simplify the process.

That said, none of them come with any warranty to work or against data loss. But, as I say, you can minimise any loss by just taking a backup.

You can use something like CloneZilla to make the initial backup to an external drive. I think it also supports network locations too so you have options available if you can't clone to an external USB disk.


For some reason, I don't trust linux tools dealing with NTFS because of a lot of bad experiences. Windows comes with a good disk management tool for FAT/NTFS, and I'd say that's your best bet. I've done this for a lot of people I've initiated into Ubuntu, and it's never failed.

  1. Boot into Windows
  2. Press start+r to open run
  3. Open compmgmt.msc
  4. Select Disk Management > Local (snap-in)
  5. Right-click the bar representing your C: partition, and hit shrink volume
  6. Wait a while as it queries available space [should be enough]
  7. Tell it how much you want to shrink by
  8. It should leave a black unallocated segment for you to do anything with.

You should now has as much free space as you asked for; do what you want with it =)

  • 1
    Circa 2000, I'd have thought the same... But nowadays I'd take open source over Microsoft every time. It's not like you get any more of a warranty with Microsoft products.
    – Oli
    Dec 14, 2010 at 15:42
  • 3
    Furthermore, this doesn't negate any need to back things up. Your first step should still be to clone the disk to an image somewhere.
    – Oli
    Dec 14, 2010 at 15:47

Before starting repartitioning, I recommend to create a disk image from the whole disk. You can use Clonezilla for this. Simply burn the ISO to a CD, have an external HDD available.

When running Clonezilla, choose device-image; local_dev; savedisk and continue. (screenshots)

I've resized a few computers with Win7 on it, and only in one case Win7 refused to start up, displaying an error message. Using the recovery mode of Win7 to run Startup repair fixed this.


If it were me I would resize the partition and create a new one from within windows7 I'm fairly sure that should anything go wrong you would still be "Under Warranty" as you are using the software that came with the PC. If you use Ubuntu and something goes wrong (not that it would) it could possibly break the warranty.


Whatever you do (i.e. from Ubuntu or from Windows), make sure not to delete your recovery partition that most likely came with your machine.


Ubuntu 9.04 totally destroyed my Win7 install (even the MBR was unreadable afterwards) once, but it was because my PC had a very weird configuration (it had a mixed PATA/SATA configuration, with apparently the boostrapper for Win7 and Win7 itself being on different drives). Apart from this one case, I installed Ubuntu (up to version 10.10) several times on different computers (desktop, notebook) hosting Win7, without a problem. The tool for resizing partitions included with Ubuntu seems rock solid to me. A Windows tool like PartitionMagic, on the other hand, failed me several times on very simple tasks, so even when I don't need to install anything, for any partition-related task I'd rather rely on a good ol' linux tool like gparted.

Conclusion: you will be fine, but save your data first (general IT motto). And your new PC came with legal Win7 key you can use with any Win7 image, in case you wonder. Just make sure you have that key and even an install failure will not cost your more than the time to reinstall.


it is pretty safe to install Ubuntu next to Win7, I have done so a couple of times without hassle. Just a couple of pointers that will probably make me win the Capt. Obvious award:

  • Depending on your machine, you might encounter some probs with your wifi (especially of you'll be installing Ubuntu on an " older" machine. So, keep a cable at hand, you might need to download some new drivers.
  • Create a part of your harddisk to be FAT32 so you can use certain files (mp3, documents,etc.) both in Win7 and Ubuntu.
  • Be patient and enjoy the experience; if you have not fiddled with Ubuntu before you'll be in for a pleasant treat.


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