diff --git a/app/controllers/concerns/commentable_actions.rb b/app/controllers/concerns/commentable_actions.rb
index 8a224c326..cdd2da4ae 100644
--- a/app/controllers/concerns/commentable_actions.rb
+++ b/app/controllers/concerns/commentable_actions.rb
@@ -28,7 +28,7 @@ module CommentableActions
 
   def new
     @resource = resource_model.new
-    prepare_new_resource_documents
+    prepare_new_resource_documents(@resource)
     set_geozone
     set_resource_instance
   end
@@ -113,28 +113,28 @@ module CommentableActions
       nil
     end
 
-    def prepare_new_resource_documents
-      if @resource.class == Proposal || @resource.class == Budget::Investment
-        (1..@resource.class.max_documents_allowed).each do
-          @resource.documents.build
-        end
+    def prepare_new_resource_documents(resource)
+      return false unless resource.try(:documents)
+      (1..resource.class.max_documents_allowed).each do
+        resource.documents.build
       end
     end
 
     def prepare_edit_resource_documents(resource)
-      if resource.class == Proposal || resource.class == Budget::Investment
-        (resource.documents.count + 1 .. resource.class.max_documents_allowed).each do
-          resource.documents.build
-        end
+      return false unless resource.try(:documents)
+      (resource.documents.size + 1 .. resource.class.max_documents_allowed).each do
+        resource.documents.build
       end
+      resource
     end
 
     def parse_documents(resource)
+      return false unless resource.try(:documents)
       resource.documents.each do |document|
         document.user = current_user
       end
-      resource.documents = resource.documents.select{|document| document.valid? }.each do |document|
-        document.attachment = File.open(document.cached_attachment)
+      resource.documents = resource.documents.each do |document|
+        document.attachment = File.open(document.cached_attachment) if document.cached_attachment.present?
       end
     end
 
diff --git a/app/controllers/proposals_controller.rb b/app/controllers/proposals_controller.rb
index f94f7b1e5..5a40d955b 100644
--- a/app/controllers/proposals_controller.rb
+++ b/app/controllers/proposals_controller.rb
@@ -30,6 +30,7 @@ class ProposalsController < ApplicationController
     if @proposal.save
       redirect_to share_proposal_path(@proposal), notice: I18n.t('flash.actions.create.proposal')
     else
+      @proposal = prepare_edit_resource_documents(@proposal)
       render :new
     end
   end
diff --git a/app/views/documents/_nested_form_fields.html.erb b/app/views/documents/_nested_form_fields.html.erb
index 10a3f7d11..e5afde8a2 100644
--- a/app/views/documents/_nested_form_fields.html.erb
+++ b/app/views/documents/_nested_form_fields.html.erb
@@ -20,6 +20,9 @@
       <%= document_fields.label :attachment, t("documents.form.attachment_label"), class: 'button hollow' %>
       <div class="progress-bar-placeholder"></div>
       <p class="file-name"><%= document_attachment_file_name(document) %></p>
+      <% if document.errors[:attachment].any? %>
+        <div class="error"><%= document.errors[:attachment].join(", ")  %></div>
+      <% end %>
     <% end %>
   </div>
   <hr>