Why can't I resize my existing partition? I just finished downloading my copy of Lion and wanted to install it on a new second partition. I freed up just over 50 GBs from my hard drive and am now stuck trying to shrink my existing partition. I'm using the Disk Utility, but am continually getting:


  Partition failed
  
  Partition failed with the error:
  
  The partition cannot be resized. Try
  reducing the amount of change in the
  size of the partition.


I've tried just resizing by 1 gigabyte and it still fails. Any free tools to fix this? Thanks.
You've probably got fragmentation of your free space. For some reason, Disk Utility can't figure this out on its own; it just fails.

I found a stunningly simple way to resolve this: create a new disk image with Disk Utility that's a little bit smaller than the remaining space on your drive.

It took several minutes on my SSD, presumably while OS X moved things around. I imagine it would take significantly longer on a hard drive.

When it's done, delete the disk image you just created. You should now be able to resize your partition!