Hey, Installed sierra this morning and couldn't believe that I had about 60gb free space after the installation - before it was about 30gb free. MacBook Air 2012 128GB. I first thought maybe this has do to with the cloud outsourcing of languages, fonts etc. I didn't go for the cloud optimization if disk space gets cramped. Under "about this mac" where you can see your drives, it shows a block as "erasable" (actually don't know what it says in english, I'm from Germany) which is about 25GB. "Löschbar" in german. Going to disk utility there is also an erasable-block and underneath it says free space only 35GB. What i want to point out is that the free disk space of my macintosh hd on my desktop is not the actual free disk space which I find very annoying. I don't want to outsource everything to iCloud and get rid off my data redundancy. Check out the screenshot. What do you think about this? Am I missing something? Total BS!