When upgrading to Premium service - watch out for duplicate calendar entries

I'm using a Windows Mobile device, with Nuevasync to sync with my Google Calendar. I was a free user for a while; but after I upgraded to Premium service I started to notice some duplicate entries in my Google Calendar (for events older than 2 weeks).

What seemed to be happening was this:
My device would previously sync up to 2 weeks in the past (per Nuevasync's setup for free accounts). However, there were several months of past event in my calendar -- because events older than 2 weeks ago seem to be left untouched after each sync (which is fine with my). Then when I upgraded to premium, it appears that Nuevasync was trying to reconcile all those older events, which resulted as "duplicate" entries in Google Calendar. More specifically, they were events from my work and other calendars copied to my default calendar.

I think this issue will be most noticeable if you use multiple calendars. The problem would manifest itself every time I would perform a "Reset Calendar" on the nuevasync.com website. What was especially frustrating were all the duplicated (and triplicated) events I had to delete which were copied from the "US Holiday" and "Contact Birthday" calendars I subscribe to in Google Calendar. Those went back over a year!!

Call me an idiot for being "fooled" twice, but also call me a geek for beta testing this: after successfully clearning out tons of duplicate entries, I reset my calendar (at nuevasync.com) and synchronized again to prove to myself that this was in fact the issue. And guess what? Yep -- spent more time cleaning out duplicate events

The solution: Don't just "reset" calendar on the nuevasync.com website, but also perform the old-school reset on your phone (go into ActiveSync options, and uncheck "Calendar" -- then check it again and resync).

We have seen this happen with one other Windows Mobile phone, and changes were made after investigating that incident to the service that should avoid the problem in the future (but any phone that had old events prior to the change would unfortunately still exhibit the problem).
Our calendar duplicate removal tool is usually able to remove the events duplicated into the primary calendar:
http://wiki.nuevasync.com/wiki/bin/view/Public/deDuper

Thanks for the info!

And thanks for the link to the duplicate removal tool. I would probably be a little wary of using something like that without more detailed control over what gets removed (for example, I may want to choose which calendar gets to "keep" the duplicate event); but it's good to know for the future.

Keep up the good work.

Yeah, the tool is designed primarily to fix duplication issues that have been observed in the past via the service and the devices used with it.
So in the case of cross-calendar duping it always removes the event from the primary calendar (which is what you'd want).