How to remove the delete option form activeAdmin?

Another way to remove actions from default_actions for an ActiveAdmin resource is via config variable, like:

    ActiveAdmin.register MyUser do
      config.remove_action_item(:destroy)
      ...
    end

One way is already mentioned in the accepted answer via actions method.

At some point I had this problem, because of the destroy method, the 'Delete' button didn't disappear

actions :all, except: [:destroy]

controller do
  def destroy # => Because of this the 'Delete' button was still there
    @user = User.find_by_slug(params[:id])
    super
  end    
end

The accepted answer threw an exception, "wrong number of arguments" so I did this to exclude the delete button(:destroy action)

ActiveAdmin.register YourModel do
  actions :index, :show, :new, :create, :update, :edit

   index do

     selectable_column
     id_column
     column :title
     column :email
     column :name

    actions 
   end

You add a call to actions to every Active Admin resource:

ActiveAdmin.register Foobar do
  actions :all, :except => [:destroy]
end