I’ve got one system that has this warning on the dashboard. I’ve looked though all the local calendars via the gui but can’t find any event that uses count for a recurring event.
A calendar you have added has an event that has a reoccuring rule of COUNT. When COUNT is used this slows down Calendar drastically. Please change your rule to another format
is there some way I can search the database to find and remove this event if it exists?
You should look at your events because something is using the COUNT rule (look at the first example here. The COUNT rule allows to set the maximum time a recurring event will repeat.
The warning is here because the matches will take much longer and the calculation becomes very intense.