I got the email from Apple saying that i was chosen one of the public beta tester of OS X Yosemite, just in case i set up a new partition to install this beta version. But after installing the OS in new partition, i tried to go back to my previous Mavericks settings by pressing on 'option' key while rebooting, and saw that the disk did not exist. Frustrated, but i managed to find the original disk in the booting disk selection corner in the System Preference panels. So i just decided to install Yosemite in the original disk and wipe out the additional partition that i created. HOWEVER!!! i cannot delete this partition now. Don't have a clue why, but when i go into my disk utility, i see this image. 1. the '-' button is not active 2. I am guessing that i need help on how to delete the logical volume group "OS X Yosemite" in the picture Need help from u guys! How can i delete the logical volume group???