I have been having this problem for a while now. We do not have wireless syncing with our BES server (according to our admin folks) Every time I connect my 7520 to my computer, Wireless sync for the calendar is enabled. I have to manually disable it through the desktop software before syncing my BB or my calendar doesn't update. My admin even removed the option to enable wireless syncing on my HH and it still does it. Hope you find a solution!