I am using Google Sync and have all my calendar data syncing between my phone and my Google calendar. I upgraded to 4.5.0.124 the other day and since then I have double entries for every calendar event. My BlackBerry email account and my college email account both show the same calendar entries. How do I turn off one calendar or stop this from happening?
Exact same thing happened to me, this is what I did.
Calendar>Options>Select Calendar
Here you'll see "Show All Calendars" and the option to select either one individually. Pick the one you'd like to clear. Also pick Agenda View. Now go to the farthest date available and with the bar on the date selected, click menu and the "Delete Prior." This will delete all calendar entries before the date selected, so be sure to choose a date that comes after your latest calendar entry.
Also in Google Sync, consider disabling the option of calendar sync (Options>Calendar>uncheck "Sync Calendar"). This is what gave me the duplicate entries.