Change WordPress user roles and capabilities › Forums › Give user access to plugin – how to › Prevent Admin user from removing other Admin users › Reply To: Prevent Admin user from removing other Admin users
I suppose you try to revoke capability from administrator role. URE does not allow this to prevent accident lose of access to the site management.
Workaround – create a full copy of administrator role, revoke unneeded capabilities from it. Grant it to your other admins.