Prevent Calendar on Mac from removing old entries I'm using El Capitan, and I went to my Mac to check my calendar (which is sync'ed to iCloud). I needed to check the details of an appointment I had 3 years ago. I went back, opened that month, and I saw all my entries. And then after a second, they vanished.

Why did this happen, and how can I stop this from happening?

And, can I use Time Machine to retrieve my old Calendar entries?
The problem is resolved.

On my iPhone, all the old entries were still there. But restarting the Mac and going to Calendar again, the same thing happened: The old items displayed and disappeared. However, disabling the iCloud calendar and then re-enabling sync for my iCloud calendars appears to have caused the problem to resolve.