I'm trying to shrink some partitions on my laptop so I can dual boot another OS, and I need about 6GB of space to do this.

Unfortunately when I got my laptop and trashed the default Vista install, I didn't think ahead about this and I ended up making an Extended partition in the free space, and I've been using it since then.

I've managed to already shrink it by nearly 12GB, but I can't then create a primary partition in the free space because it seems the extended partition wants to remain the allocated owner of this space.

I was hoping I could get somewhere with diskpart but I got as far as shrinking the same volume another 6GB (and hence it is now 12GB).

My question is: can I unallocate (shrink) the Extended partition so I can create a primary partition, or do I have to remove the extended partition so a primary partition can exist in front of it?

  • what "other OS" do you want to boot? – quack quixote Jan 14 '10 at 20:32
  • I had a similar problem not to long ago. I poorly estimated the amount of space for the primary partition. My theory on why the 'c' partition cannot be expanded is that the drive manage desires to keep the 'c' partition continuous. If I might continue to hypothesize if one used a degfragmenter to move the data to the end of the partition prior to shrinking. one might be able to shrink the leading edge. But then I solve my problem with a second hard disk. A partition app like partition magic may do the trick. – greyDrifter Jan 15 '10 at 5:17
  • @greyDrifter: That's an interesting point about keeping the partition continuous - I think you're right, but I can't install another disk on my laptop. My last resort is to use partition magic or some sort to image the D drive so I can delete the extended partition, in order to create a new bootable one. Not my personal preference but I'm willing to go there. – Codesleuth Jan 15 '10 at 9:15

I only rarely use it, but it seems like something that GParted could do from the Live CD. It may even be specifically addressed in http://gparted.sourceforge.net/larry/resize/resizing.htm

  • GParted worked to move the extended partition over tot he end of the disk and create some space, but I have reached my limit of primary partitions and unfortunately can't create a new one. Joshua Nurczyk's answer suggests I don't need to create a new primary partition but I'm not sure that's true. :( – Codesleuth Jan 21 '10 at 10:16
  • Not sure, you're in uncharted territory for me (OSX). I agree with him that all the dual boots I have set up using linux (in my case Ubuntu), it just works and when done booting just means picking which OS will start (default depends on install method). I don't know if you've looked at en.wikipedia.org/wiki/Disk_partitioning but if not it may shed some light. Good luck, you might want to try a question that mentions OSX and dual booting up front. Or if you just want to play with a secondary OS you might try Virtual Box. – Dennis Jan 21 '10 at 13:25
  • I've marked you as the answer because GParted did most of what I wanted. However, OSX won't boot from a logical partition within an extended partition - it just won't work. Anyway, thank you both for your answers :) – Codesleuth Jan 27 '10 at 9:54

It depends on what OS you want to boot. Most versions of Linux and Windows from the past few years should have no problems with being put in an extended partition on that space. The specific answer of course depends on what you want to do.

  • Just to double check what you say, I booted the OS up again (it's OSX x86 by the way) and sure enough I got through the installer to the part that asks for the drive to install to, and it doesn't show the empty space. I'll play with it tomorrow, it's getting late now :( – Codesleuth Jan 14 '10 at 23:51
  • I got the OS installed but it didn't boot from the partition within the extended partition. I don't know much about altering boot records and what-not so it could just be because I need to change that? – Codesleuth Jan 21 '10 at 10:14

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