So, I installed my Yosemite Developer Preview on a separate partition on my MacBook Pro with Retina Display 13", late 2013 $1499 model. (remained unchanged in last update) Thinking I was clever, I thought I could use it casually then wipe it and install the real thing over my Mavericks when it came out. Herein lies the problem: I no longer appear to be able to control either of the partitions from any part of the OS. They are greyed over in Disk Utility whether I am in Yosemite, Mavericks, or Recovery. I'm not that good with Terminal yet, but I have a feeling the solution is going to involve it at this point. On a side note, I incompletely wiped a Windows partition a while back, but the Windows partition is still visible when I hold down alt at startup. Any ideas as to why? It's invisible in Disk Utility and Startup Disk but I can still see it if I hold alt at startup. I thank you graciously for any help you can provide. Thank you.