File Options specifies an account name and password also. If you have no password defined, this setting should specify an Account Name of "Admin" and no password. That then opens the file with the default full password setting.
It would be a good idea to add an account name and password and then use File Options to open the file with it automatically so that your user isn't asked for a password. I've seen cases where an uninformed user accidentally modified a layout simply because they accidentally pressed the keyboard shortcut for layout mode. Thus, a limited privileges password set in File Options or the guest log in option would be a simple way for your users to access the file in such a way that they can't have such an "accident". And you can still open the file with a full access password by holding down the Shift (windows) or option (Mac) key while opening the file.
I worked out that what I did was to uncheck the "Log in using:" & Account name and password. This threw up the prompt every time.
On reflection though you are right, I am going to adjust the database to require the login but without password and configure accounts with limited privileges. I have just discovered the Get ( AccountName ) function which will help to eliminate the users irritation at the login.
Thanks again phil, you are a legend!