Partition MacBook Pro with Mac OS X Lion using Disk Utility I've just bought a new MacBook Pro with Mac OS X Lion.

The problem started when I tried to divide the hard disk into more than 3 partitions, so I erased the existing partition and tried to divide the hard disk using Disk Utility. So, I opened the "Partition" tab and chose "3 partitions" and when I hit "Apply" it says that "Couldn't unmount partition".

Can anyone please tell me how to fix that or how can I partition my hard disk?
ALERT: THIS WILL ERASE YOUR DATA WHEN YOU PARTITION. PLEASE BE SURE THAT ALL IMPORTANT INFORMATION IS BACKED UP VIA TIME MACHINE OR OTHER METHODS!

Load  OS X Lion from a USB Flash Drive or DVD from your post screen by holding option on your MacBook Pro's startup. Open Disk Utility from there, and repartition your hard drive to your desired specifications. Remember: this will erase your data (files and programs), and all of your data will need to be reloaded.