Originally Posted by aiharkness
With regard to the sync erroring out on calendar, take a look though the calendar on the computer. If you can change the view to rows and columns like a spreadsheet, all the better. Look for oddball characters, empty rows, and so forth. Clean up as needed. Also look at notes in calendar entries, particularly any that are relatively large in size. After you've cleaned it up, try to sync again. If you still have trouble, use advanced backup/restore to clear the calendar database on the device and then re-sync. Hopefully it works.
As far as dupications and that sort of thing, I don't know, except set desktop manager to ask for confirmation, and re-sync when it asks to make what you think are too many deletions, additions, or changes.
Ira - This appeared to be the problem. Apparently, the Blackberry software does not work well with Macs (not sure which is at fault here). But when I'd synch, all my repeating events on my Mac would get replicated. I'm not sure how many times (possibly hundreds), but they were all layered on top of each other so I couldn't see them. So when I'd go to synch, it couldn't be completed due to all the info that was being stored.
Anyway, so I "solved" it by wiping my blackberry and deleting my calendar on my Mac and then creating separate calendars for repeating events and one-time events. I don't synch my repeating events calendar. While this isn't ideal, it's better than not being able to synch at all.