sorry. macbook pro; mid-2012; running yosemite 10.10.3
i have, i think, re-downloaded and re-installed both the beta and feb 2015 version 3 times in the last 2hrs. I got one the older version to stick, but it didn't have the mega bar rgba i needed, so i deleted it and started another beta download, etc. I shouldn't have done that. Got greedy and now nothing works.