bobkow wrote:
I did create a new user and opened up Calendar and I got a new, blank Calendar filled in with standard holidays. So the app works. But not the app that is in my User file.
I want to try this; delete everything in the calendar folder and library and then create a completely new calendar file from scratch. Then I would import my calendars from iOS.
Considering what you have already tried, I am hesitant to provide additional recommendations. Since I know nothing about how Fantastical may have affected your installation, perhaps Fantastical Support may provide you with some suggestions to ensure that it was completely and properly uninstalled.
It might also be helpful to review the Calendars Folder structure in the new user account, and compare it to the structure in your active user account. Then delete only those items which differ. It sounds like Calendars still refuses to open, but if opened make sure that "Enabled" is deselected in Calendars>Preferences...>Accounts>iCloud.
If you decide to "delete everything" in the Calendars Folder in your Home Folder, make sure that you have a bootable backup of your computer. I have not attempted that, but after deletion I would consider disabling iCloud Calendars in System Preferences>Internet Accounts>iCloud>Calendars, and using the macOS Mojave 10.14.5 Combo Update.
Since I have not tried any of these procedures, my post should not be construed as describing what you should actually do. My comments are only presented for your consideration.
