For many of us developers, testing OS X Lion is very high priority. This is how I installed OS X Lion into a separate partition on my MBP.
Obviously, before you start repartitioning your system, please back it up. A zillion things can go wrong when you start moving and resizing partitions. You’ve been warned.
Notes:
* The first time you run Mail, your mailbox is “converted” to the new system. I’m assuming that you won’t ever be able to run the old version of Mail!
* If disk utility is unsuccessful in creating your new partition, reboot into the Lion OS X image and select Disk Utility from the menu there. That will run Lion’s new Disk Utility which is more robust that the older version. OS X Snow Leopard was never able to repartition my drive but OS X Lion had no problems.
* Playing with partitions is not for the faint of heart. Installing OS X Lion to a USB drive or external hard drive is a safer but likely slower option.
* Expect to find and be sure to report any bugs you find within Lion.
Directions:
1. Open Disk Utility
2. Click your drive and select the First Aid tab
3. Verify Disk and Repair Disk if needed
4. Click the Partition tab
5. Click the + sign and create the new partition and name it. I would make sure it is at least 20GB in size. My OS X Lion completed install was just under 10GB.
6. Boot to your OS X Lion image. I mounted mine on a USB drive.
7. Install OS X Lion and be sure to select the new partition you just created.
8. Boot into OS X and enter basic information
9. You will probably want to link your old and new home directories by doing the following:
– a. Open Users & Groups in System Preferences
– b. Unlock to allow changes by clicking the lock and entering password
– c. Right-click on your admin account and select Advanced Options
– d. Choose your old Home Directory and leave everything else alone.
– e. You will be forced to reboot. Upon reboot your system will closely resemble your old setup
10. You may wish to link to your old applications. I just put an alias from my old application directory in my dock. Even after linking home directories and applications, some applications may not work reliably.