You need matching account names and passwords in each file. This is one reason why it can be nice to put all your tables in one file--it simplifies the account management issues involved.
Ways to manage multiple accounts across multiple files:
If your are using server, set up external server authorization.
Scripts can be set up that create identical accounts and passwords in a set of files. You enter an account name, a password and a privilege set name into fields and then a script does the rest.
"Utility files" for which all users need the same level of access can be set to auto enter a limited access account name and password in File Options for that file. The developer can still open the file with full access privileges if they hold down the shift (WIndows) or option (Mac) key while opening the file.