Okay, this just happened recently and I can't seem to figure a way of fixing it short of a hard-reset back to factory defaults. There was an error that occurred with it, but because I was working on something at the time, I didn't get a good look at what the error message was. The issue I currently have is the Calendar Storage will fail to work certain times requiring me to disable/enable it again to get it working. It will be okay for a few days, then it'll start to act up again. The calendars will simply disappear and fail to appear for selection. I think something in the OS really got buggered up because of it. I already went in to system recovery and tried clearing the cache partition, which didn't fix the problem. Any other suggestions I could try? I'm currently doing a backup of my phone logs, messages, etc. Only real annoying thing will be losing progress and app data (not rooted). Unless someone knows of a way around it?