diff --git a/app/controllers/default/units_controller.rb b/app/controllers/default/units_controller.rb
index e6dd2ed..6ca2733 100644
--- a/app/controllers/default/units_controller.rb
+++ b/app/controllers/default/units_controller.rb
@@ -1,7 +1,8 @@
 class Default::UnitsController < ApplicationController
   navigation_tab :units
 
-  before_action :find_unit, only: [:import, :export, :destroy]
+  before_action :find_unit, only: :export
+  before_action :find_unit_default, only: [:import, :destroy]
 
   before_action only: :import do
     raise AccessForbidden unless current_user.at_least(:active)
@@ -15,7 +16,9 @@ class Default::UnitsController < ApplicationController
   end
 
   def import
-    raise ParameterInvalid unless @unit.default? && @unit.port(current_user)
+    @unit.port!(current_user)
+    flash.now[:notice] = t('.success', unit: @unit)
+  ensure
     run_and_render :index
   end
 
@@ -26,16 +29,26 @@ class Default::UnitsController < ApplicationController
   #end
 
   def export
-    raise ParameterInvalid unless !@unit.default? && @unit.port(nil)
+    @unit.port!(nil)
+    flash.now[:notice] = t('.success', unit: @unit)
+  ensure
     run_and_render :index
   end
 
   def destroy
+    @unit.destroy!
+    flash.now[:notice] = t('.success', unit: @unit)
+  ensure
+    run_and_render :index
   end
 
   private
 
   def find_unit
-    @unit = Unit.find_by!(id: params[:id], user: [current_user, nil])
+    @unit = Unit.find_by!(id: params[:id], user: current_user)
+  end
+
+  def find_unit_default
+    @unit = Unit.find_by!(id: params[:id], user: nil)
   end
 end
diff --git a/app/models/unit.rb b/app/models/unit.rb
index fbb2c8e..027c492 100644
--- a/app/models/unit.rb
+++ b/app/models/unit.rb
@@ -97,11 +97,11 @@ class Unit < ApplicationRecord
     user_id.nil?
   end
 
-  def port(recipient)
-    recipient_base = base && Unit.find_by(symbol: base.symbol, user: recipient)
-    return nil if recipient_base.nil? != base.nil?
+  # Should only by invoked on Units returned from #defaults_diff which are #portable
+  def port!(recipient)
+    recipient_base = base && Unit.find_by!(symbol: base.symbol, user: recipient)
     params = slice(ATTRIBUTES - [:symbol, :base_id])
     Unit.find_or_initialize_by(user: recipient, symbol: symbol)
-      .update(base: recipient_base, **params)
+      .update!(base: recipient_base, **params)
   end
 end
diff --git a/app/views/default/units/_unit.html.erb b/app/views/default/units/_unit.html.erb
index 13c2d9e..83e605b 100644
--- a/app/views/default/units/_unit.html.erb
+++ b/app/views/default/units/_unit.html.erb
@@ -11,7 +11,8 @@
       <% end %>
       <% if current_user.at_least(:admin) %>
         <% if unit.default? %>
-          <%= image_button_to t('.delete'), 'delete-outline', unit_path(unit), method: :delete %>
+          <%= image_button_to t('.delete'), 'delete-outline', default_unit_path(unit),
+            method: :delete %>
         <% else %>
           <%= image_button_to t('.export'), 'upload-outline', export_default_unit_path(unit),
             disabled_attributes(!unit.portable?) %>
diff --git a/config/locales/en.yml b/config/locales/en.yml
index ff3c4fd..fe127bb 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -33,6 +33,9 @@ en:
         forbidden: >
           You have not been granted access to this action (403 Forbidden).
           This should not happen, please notify site administrator.
+        not_found: >
+          The record that you requested operation on does not exist (404).
+          This should not happen, please notify site administrator.
         unprocessable_entity: >
           The request is semantically incorrect and was rejected (422 Unprocessable Entity).
           This should not happen, please notify site administrator.
@@ -77,6 +80,12 @@ en:
         actions: Actions on defaults
         import_all: Import all
         back: Back to units
+      import:
+        success: Imported unit "%{unit}"
+      export:
+        success: Exported unit "%{unit}"
+      destroy:
+        success: Deleted unit "%{unit}"
   users:
     index:
       disguise: View as