Hi
In schema browser Users tab, there could be a button which can be toggled on/off, which tells whether to show only user created users (oracle_maintained='N') or all users.
The thing is, most (or even all) of the time when something needs to be done with users, we do this with user created users.
We shouldn't be doing anything with oracle created users (oracle_maintained='Y') except change password etc.
Also, after changing this option and closing toad, and reopening again, it should remember this setting.
Regards
Raul