I have a late 2009 Macbook (white unibody) and I'm trying to upgrade to Yosemite. I keep getting an error message saying that I don't have enough memory to do so. However, I know there is very little on the hard drive (SSD replaced by me less than a year ago). Running my disk utility, it says I have 200GB of 240GB available. There is only a single partition to the drive. So, I'm stuck and coming here for suggestions. And, FWIW, I upped the RAM to 8 GB years ago. Anyone have any thoughts?