Operation failed when I tried to create a partition I'm trying to create a partition in following "Part 2: Preparing your Mac" from this website. I have to create "Ubuntu Boot Loader" in selecting the principal hard drive "APPLE SSD AP0512J Media", select Partition -> + -> Name : Ubuntu Boot Loader -> Format : Mac OS Extended (Journaled) -> Size: 128 MB, but I got the following error with Disk Utility : 





I got the following message when I hit "Show Details" : 


  Running operation 1 of 1…
  Checking prerequisites for resizing Logical-Physical volume stack
  The requested size change for the target disk or a related disk is too small. Please try a different disk or partition, or make a larger change.
  Operation failed…




Could anyone be able to tell what do I have to do to fix the "Operation failed"?
Like it says in the error box, try making a bigger partition. The partition you are trying to create is only 128 mb. Even though it says create a 128MB partition(in the guide), it wouldn't cause any problems to increase the size of the partition since there are errors for creating a partition of the size 128MB.