I just cloned my failing 250 GB hard drive onto a 500 GB hard drive (so I wouldn't have to re-install everything, etc.), but now the drive only thinks it is 250 GB. How do I tell it about the other 250 GB of space available on the drive? Preferably I'd like to just resize the partition so it takes all 500 GB of space, but I'd settle for mapping the other 250 GB to another drive letter.

This is in Windows XP.

  • If you run diskmgmt.msc does it show unformatted space on the disk?
    – Lukas
    Commented Nov 27, 2010 at 6:45
  • Note that special care is needed when migrating to an SSD disk. Commented Dec 22, 2015 at 5:48

3 Answers 3


You cannot resize Windows system partition while being booted from that partition, so you should use an external tool for this purpose.

Personally, I prefer PartedMagic: it is a very good and stable Linux-based partitioning tool which you can start from CD or a flash drive. The interface is obvious enough, but if you have any questions, you can leave a comment.

  • 2
    correction: PartedMagic is NOT a partitioning tool, it's rather like an OS, a Linux-distribution, which contains useful programs like GParted and Parted - which ARE partitioning tools.
    – Sk8erPeter
    Commented Dec 24, 2011 at 3:53
  • 2
    @Sk8erPeter that does not matter to an end user. Being a Linux distro et al is just a side effect.
    – Catherine
    Commented Dec 25, 2011 at 11:53
  • 2
    yes, the majority of users don't even really care about what they use, they just want it to work. I just wanted to clarify that the partitioning tool is GParted and Parted - not PartedMagic, which makes it possible to use these partitioning tools. :) Don't be upset about that, it's just a correction. :)
    – Sk8erPeter
    Commented Dec 25, 2011 at 21:04
  • 1
    Isn't PartedMagic a re-packaged, paid version, of the free GParted? - gparted.org
    – laurent
    Commented May 23, 2014 at 17:49
  • 1
    PartedMagic is no longer free software, an open source alternative might be gparted.org/livecd.php Commented Mar 20, 2018 at 15:13

Try EASEUS Partition Master. You can run this from Windows itself, and it's free for home users.

  • Is this program really reliable? I don't have any experience with it, but I'm a little bit suspicious of Windows-based programs, when such critical operations have to be made.
    – Sk8erPeter
    Commented Dec 25, 2011 at 21:08
  • 2
    @Sk8erPeter looks good, even Lifehacker has an article on it: lifehacker.com/399871/…
    – Tim Büthe
    Commented Aug 23, 2012 at 11:33
  • @TimBüthe: and then what? :) The article you showed me is just an introducing text about this program (what this is all about), nothing more. It doesn't prove anything at all.
    – Sk8erPeter
    Commented Aug 23, 2012 at 12:00
  • 1
    Well, since lifehacker is a legitimate and respectable source of software recommendations I thought this would get it some points on your trust scale. Never mind, I guess you just have to try it out, worked fine for me though.
    – Tim Büthe
    Commented Aug 23, 2012 at 12:16
  • Beware that it tries to install some adware in there too. Make sure you click the Customized Install for EVERY option!
    – dano
    Commented Mar 6, 2015 at 20:15

You could try to boot from a Linux live CD and run Gparted, it may work for you.


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