How to erase all files of the Calendar?

Hello teodrick,

Thank you for using Apple Support Communities.

If you are wishing to delete calendars from the Calendar app on El Capitan. That is not difficult to do, following is how to do it:

Delete a calendar
Click the calendar’s name in the calendar list.

If you don’t see the calendar list on the left, choose View > Show Calendar List.

Choose Edit > Delete.

There are some calendars that can't be deleted. For more information, see the following article:

Calendar (El Capitan): Add or delete calendars

Regards

Hi teodrick,

For the connection speed concerns you may be better served by using another one of Apple's support resources - https://getsupport.apple.com/GetproductgroupList.action.

Cheers

teodorick wrote:

my Question is how to reset all preferences and setups of Calendars, or what to do to have it as if it was new and empty.

In Internet Accounts, disable/delete any Calendar accounts you have created--disable if it is part of a larger account like iCloud or Gmail, delete if it is only a Calendar (CalDAV) account.

Delete everything in ~/Library/Calendars.

Delete the folders in ~/Library/Containers/ that contain either Calendar or iCal

Delete the plist files in ~/Library/Preferences/ that contain either Calendar or iCal.

Delete the com.apple.ical.savedState file from ~/Library/Saved Application State/ folder.

The ~/Library notation means your user Library that is in your Home folder, not the main Library in the root of your hard drive.