Was have a problem with my Blackberry where calendar syncs wouldn't complete with a cryptic error:

Found the solution in the Missing Sync forum here:

Those of you having problems syncing calendars, have you tried resetting Sync History?

There are two ways to do this:

- From within Missing Sync
1) Choose "Reset Sync History" from the Help menu.
2) Select the calendars checkbox
3) Then click the "Reset Sync History" button

- From within iSync
1) Launch iSync
2) Open iSync Preferences from the iSync menu
3) Click the "Reset Sync History" button
4) Read the information about resetting the Sync services. Then choose the "Reset Sync Services" button.

Reset the Sync History and then connect your device and try to sync just Calendar for now. Choose "Show History" in Missing Sync and also enable "Verbose Logging" so you can send us the logs to help figure out what's going on.

Update

So the above steps didn't work for me after all. I posted the above, then started getting errors again.

So I gave up trying to track down the events in my calendar that were preventing the sync from completing.

I printed out my calendar for 2008, deleted all the calendars in iCal, and reentered the recurring events (mostly birthdays) and handful of other events coming up this year.

I didn't want to lose my calendar history, but at this point, it was more trouble than it was worth to keep it. I had already deleted events from very early such as meetings and other items from when I was still working at Archer/Malmo. But some of the birthdays were damaged recurring events from that far back, and no matter how many times I deleted and recreated those, I was still getting sync errors.

Keeping paper printouts for archive looks like the only real way to go, still. Yay, technology.