Recently, I noticed that my Macbook Pro (2009 model running Mavericks) does not update the local version of Calendar with the one on iCloud anymore. An Apple article suggested signing out of iCloud and signing back in. This did not fix the issue, but created a new one. Now, when I try clicking the checkmark box in iCloud's settings next to Calendar (System Preferences > iCloud), it loads (says "Setting up..."), but the box is never checked. Does anyone know how to fix this and get my Macbook finally syncing with iCloud again? All I want is for my iPhone's calendar to stay up to date.