I originally decided to take a 2 partition method by having Mavericks and Yosemite on the same drive, with most of the space dedicated to Mavericks and about 100 something gbs for Yosemite. However, I've decided I want to just delete Mavericks and take Yosemite as my regular OS (since my only broken app, FCPX, has a work around). However, I've noticed a unique issue I've never encountered with any of the betas before - I have no control over my partitions, at all. Here's what Disk Utility looks like: I tried formatting Mavericks to see if I could merge it with the Yosemite drive but that did nothing, and doing it in diskutil just freed up the unpartitioned space. Here's what I'm thinking - Since Mavericks was the main OS and that's what OS i used to partition the drive, do I need to use Mavericks again to access the partitions? Or, will running the Yosemite installer allow me to run terminal so I can run diskutil and manually erase the disk? Would running the installer off of the flash drive restore my control of the Disk Utility? Does Yosemite's installer even give access to the Terminal? Does Mavericks? Does the Internet Recovery Drive allow the Terminal (that would mean going all the way back to Lion, crazy)? I've never encountered this issue using the Mavericks beta, so this is odd. Worst case I have to use an external source to format the drive, right? This is all so crazy. Thanks for any help.