Did you first create a new workgroup information file? If not you are
modifying the standard system.mdw that ships with Access, and you really
don't want to do that. If you want to secure a database, please download
and study the security FAQ available from
Be sure to follow every step outlined or your database won't be secure.
If I understand you correctly, you've gone to Tools, security, User and
Group Accounts and added a new user. Automatically that user will be made a
member of the Users group and nothing else. To add them to the Admins
Group, you select Admins under 'Available Groups' and click on the Add
button to the right.
But as I said, you shouldn't go any further before reading the FAQ. Other
good sources of information are
Although the whitepaper is old, it contains information to help you
Microsoft Access MVP