Missing calendar items intermittently

[Richard Poon]

One of the Outlook user has a strange issue on the calendar. From time to
time, nearly all of his past and future items disappear from his calendar and
his BlackBerry. However, his assitants can still access all the items from
his calendar. After some time, for unknown reason, those items suddenly come
back to his Outlook. When the issue occurs, I switch the calendar view to By
Category, but still don't find the missing ones. When it is viewed by
Day/Week/Month, most of the days on the monthly calendar on the top right
corner are bold, indicating that there are activities on those days.

Is there any idea to resolve the problem? I wonder if it is an Exchange
mailbox corruption.

Thanks a lot.
Richard Poon