Hi!

In Calendar app settings, the option "Show Birthdays calendar" is checked. Then, after a couple of days or so, Birthdays calendar disappears from the app because the option is unchecked on preferences. Even if I reboot my MBP or if I upgrade to latest OS version, the problem persists. It only happens on my MBP, not on iMac or iPhone or iPad; just on my Macbook Pro.

I have this problem since long time ago, maybe two years or more.

Is there any way to fix it?

Thank you!