Comment # 30 on bug 58383 from Kip Warner

(In reply to comment #29)
> The factory reset was the brute-force suggestion for finding out whether the
> data is the problem. If you don't want to do that, perhaps you can wipe out
> data for individual apps manually?

Factory reset is definitely not an option. I'd wipe out individual data, but I
don't know what specifically is making it choke and there are thousands of
calendar entries and hundreds of contacts.