Troubleshooting duplicate appearance of events, notes, tasks and to do items

After observing some duplication of events and to do items within iCal, I realised that for Google Calendar, the CalDAV account was somehow duplicated then resolved (invalidated) a Chandler bug.

I posted a question to the Calaboration area, gained advice, considered the contents of my ~/Library/Calendars directory, with particular attention to Calendar Cache* files, and the contents of the ~/Library/Calendars/Calendar Sync Changes directory.

In single user mode I cleared various caches, set aside some files, rebooted, launched iCal, relaxed and before long I saw the reappearance of the two Google Calendar CalDAV accounts that I had removed from iCal Preferences before shutting down the computer.

Thinking beyond iCal, Calaboration and Google Calendar, I launched iSync and realised that in Apple's version 3.0 conduit that applies to my Nokia N73, there were ticks in two check boxes corresponding to the mysteriously reappearing CalDAV accounts.

I allowed a fair amount of time for iSync to refresh its view of things, ensured that neither of the Google Calendar CalDAV accounts were present/checked, reviewed iCal preferences to ensure that neither of the Google Calendar CalDAV accounts were present.

Probable cause of the duplication

It's most likely that at some point, in the Preferences window of iCal, I renamed the CalDAV account for Google Calendar.

I wonder whether the duplication would have occurred if I had used iSync shortly thereafter.

The lesson

When troubleshooting, do consider all clients of Sync Engine.

The Apple illustrations represented in a recent discussion Apple Sync Services, Truth Database; CalDAV; Google Calendar, Calaboration (highlights) help us to visualise iCal as just one of a number of clients.

Now, it's probably timely for me to consider the following:

• iSync Devices menu options to Reset Device (with my Nokie N73 selected) or Reset All Devices…
• iSync Preference window to Reset Sync History….

Postscripts:

• Reset Device alone seems to have worked well.
• Apple radr://6481476

-- GrahamPerrin - 08 Jan 2009

• Screen shot of the Info window for one of two appearances of my one and only calendar at Google Calendar:
  

• first (uppermost) of two CalDAV accounts for Google Calendar:
  

• second of two CalDAV accounts for Google Calendar:
  

• one of two multiple selections of a single calendar:
  

• two of two multiple selections of a single calendar: