I just converted a solution consisting of 5 databases from FMP6.4 to 9.3. Before doing the conversion, I eliminated all username/password controls over the 6.4 databases.

Yet,the converted databases in v9.3 still keeps asking for user names and passwords to open them.

The Guest option also allows complete access to all the databases, but I do want to establish new security over the converted files.

For starters? what should I have done pre-conversion, or what can I do post-conversion to eliminate the user name/password request altogether?

The default password is "Admin", no user name is required.

All .fp7 files have a password, before this it was no necessary.

As Ideal indicated, it's sorta required now. Check under File:File Options" menu and turn on the "Login Using" to whatever one you want (the default Admin works as Ideal indicated). That will stop the prompt.