If the existing one replace with new one (old data replace to new data) then qlikview app ask you to save the document.
Are you user r admin?
if u act as admin
go to Settings->Document Properties->Security->Save Document(User) has to unchecked
then user doesnt face that issue
if u act as user
ask u admin to perform above steps
There are some security settings where we can restrict user . this can be done only by admin not user