Use custom menus to remove the Change Password command.
I'm not sure what you're attempting to do with the login file. If the accounts credentials are the same in all files, then after opening the "main" file and entering the username and password, the same username and password will be used to open the other related files.
The ideal setup is external authentication, particularly if there are a large number of users and a large number of files.
Thanks Vaughan for your reply, but looks like I was not that clear on the problem I was trying to resolve. This basically is to bypass the FileMaker login box that has a button 'Change Password' which is very confusing to a user with a multi-file application. You can stop them changing their password in the privaleges set but the button is still their and doesn't tell the user the password has not been changed.
I was therefore trying to open with a dummy user name called 'Login' which has no password. On entry a script is run with a dialog box asking user to enter user name and password. Next the script re-logs in the user under their proper user name which is the same in the other files in the multi-file application.
The problem is that as soon as you put it on a server the standard FileMaker login box returns again.
So you're popping up a custom dialog to capture login credentials? This should be completely unnecessary. It's also terribly bad practice.
If the user's privilege set does not allow changing passwords then the login prompt won't offer that option.
I'm still not sure what you're trying to do but please stop it and go back to basics: make sure all the accounts in all the files have the same usernames and passwords, set the privilege sets to not allow password changes, forget the log-in file and get the users to open the solution main file directly. All the other related files will open themselves up.