How do I get my calendars back? Recently, I ran into a problem with the Apple Calendar app on my laptop. In Fantastical, the calendars displayed correctly on both iOS, my laptop, and my work iMac. The only inconsistent place was my laptop. 

So, I went into ~/Library/Calendars and and removed "Calendar Cache". This had the side-effect of completely removing my iCloud, Google, and Facebook calendars. When I go to the accounts pref pane, I see that my iCloud calendars are enabled, but in the accounts menu item on Calendar, it is not. So, I added it back, but after signing into iCloud is a success, it still fails to appear in the left-hand calendars menu, or in the Accounts menu item. 

Though the calendars side-bar does display my Google and Facebook account, it does not display the calendars within those accounts.

What could be going on? Any ideas for how to resolve this?
Go to your account settings, delete your iCloud account, reboot, add it again.