Perrott, Greg
I notice that a database update is fired when somebody opens a contact in Outlook for the first time. Other database update is fired if the user makes any chanegs and saves them.

Why is the first update fired when the contact is first opened? Can this be stopped?

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I think you are using option. Assign Table->Options...

Outlook changes flag unread (or other flags if on MS Exchange), when opening Contact first time.
Perrott, Greg
Is there any way to stop this.

A change to unread (or other) flag should not need to by synched as they are not one of the synchronised fields.

Maybe an option like "Ignore changes to unsynchronised fields".

No, even if the unread flag is not synchronized/mapped, other fields get changed also: LastModificationTime, LastModifier etc..
This is something outside GeniusConnect. But if GeniusConnect detects that mapped Outlook fields are equal DB Fields it will display "Unchanged", and NO DB Update will be executed.