Calendar entries not appearing

Question

OK so historic and recent entries I've made on Calendar on my Mac exist only in the search bar of Calendar - meaning if I search for something I know I've entered it comes up in the search bar as an abbreviated entry there, if  I click on it it gives the date of the entry, if I go to that date though there's no corresponding entry, I think this is a problem affecting a ton of my entries/events now and is hugely frustrating.
It may also be connected with the phenomenon I've noticed of the Calendar not accepting entries, - I click on the date in question, type one and hit return and it does not appear on the calendar, sometimes this happens repeatedly.
Thanks

Answer 1

Please read this whole message before doing anything.
Back up all data.
Before taking each of these steps, quit (force quit if necessary) the application. After taking the step, relaunch and test. When the problem is resolved (or when you complete Step 3 without resolving it), stop and close the Library folder.
Step 1
Hold down the option key and select
Go ▹ Library
from the Finder menu bar. From the folder that opens, move these subfolders (some may not exist) to the Trash, leaving the Library folder open:
Caches/com.apple.CalendarAgent
Caches/com.apple.iCal
Calendars/Calendar Cache
Saved Application State/com.apple.iCal.savedState
Step 2
Move these files from the Library folder to the Desktop (again, some may not exist):
Preferences/ByHost/com.apple.iCal.helper.*.plist
Preferences/com.apple.CalendarAgent.plist
Preferences/com.apple.iCal.Alarm.plist
Preferences/com.apple.iCal.AlarmScheduler.plist
Preferences/com.apple.iCal.helper.plist
Preferences/com.apple.iCal.plist
Preferences/com.apple.iCalExternalSync.plist
Preferences/iCalExternalSync.plist
Here "*" stands for a long string of letters, numbers, and dashes. If the application now works, you may be able to put back some of the files you moved in this step, relaunching and testing after each one. Eventually you may find the one that caused the problem; delete it. Recreate your settings as necessary.
If the application still doesn't work, put back each of the files you moved in this step, overwriting the one that may have been created in its place. You don't have to put back the folders you moved in Step 1.
Step 3
Move this folder to the Desktop:
Calendars
Note: you're not moving the Calendars application; you're moving a folder named "Calendars". If there's no change, put the folder back where it was.
If the application works after you move the Calendars folder, the event database is corrupt. You have these choices:
Restore the folder from a Time Machine snapshot or other backup that predates the corruption.
Use a third-party application such as Calendar Cleaner to try to repair the database.
For network calendar accounts, such as iCloud, all you should need to do is re-enter them in the preferences.
For subscribed calendars, you only need to re-subscribe.