diff --git a/app/controllers/groups_controller.rb b/app/controllers/groups_controller.rb
index 4bd732fc..29e4e4b0 100644
--- a/app/controllers/groups_controller.rb
+++ b/app/controllers/groups_controller.rb
@@ -141,14 +141,22 @@ class GroupsController < ApplicationController
     @membership = Member.edit_membership(params[:membership_id], params[:membership], @group)
     @membership.save if request.post?
     respond_to do |format|
-       format.html { redirect_to :controller => 'groups', :action => 'edit', :id => @group, :tab => 'memberships' }
-       format.js { 
-         render(:update) {|page| 
-           page.replace_html "tab-content-memberships", :partial => 'groups/memberships'
-           page.visual_effect(:highlight, "member-#{@membership.id}")
-         }
-       }
-     end
+      if @membership.valid?
+        format.html { redirect_to :controller => 'groups', :action => 'edit', :id => @group, :tab => 'memberships' }
+        format.js {
+          render(:update) {|page|
+            page.replace_html "tab-content-memberships", :partial => 'groups/memberships'
+            page.visual_effect(:highlight, "member-#{@membership.id}")
+          }
+        }
+      else
+        format.js {
+          render(:update) {|page|
+            page.alert(l(:notice_failed_to_save_members, :errors => @membership.errors.full_messages.join(', ')))
+          }
+        }
+      end
+    end
   end
   
   def destroy_membership
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index f19cd783..023352d8 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -123,14 +123,22 @@ class UsersController < ApplicationController
     @membership = Member.edit_membership(params[:membership_id], params[:membership], @user)
     @membership.save if request.post?
     respond_to do |format|
-       format.html { redirect_to :controller => 'users', :action => 'edit', :id => @user, :tab => 'memberships' }
-       format.js { 
-         render(:update) {|page| 
-           page.replace_html "tab-content-memberships", :partial => 'users/memberships'
-           page.visual_effect(:highlight, "member-#{@membership.id}")
-         }
-       }
-     end
+      if @membership.valid?
+        format.html { redirect_to :controller => 'users', :action => 'edit', :id => @user, :tab => 'memberships' }
+        format.js {
+          render(:update) {|page|
+            page.replace_html "tab-content-memberships", :partial => 'users/memberships'
+            page.visual_effect(:highlight, "member-#{@membership.id}")
+          }
+        }
+      else
+        format.js {
+          render(:update) {|page|
+            page.alert(l(:notice_failed_to_save_members, :errors => @membership.errors.full_messages.join(', ')))
+          }
+        }
+      end
+    end
   end
   
   def destroy_membership