diff --git a/app/models/direct_upload.rb b/app/models/direct_upload.rb
index c4d1456e7..088c8ea64 100644
--- a/app/models/direct_upload.rb
+++ b/app/models/direct_upload.rb
@@ -51,7 +51,7 @@ class DirectUpload
     @relation.valid?
 
     if @relation.errors.key? :attachment
-      errors[:attachment] = @relation.errors[:attachment]
+      errors.add(:attachment, @relation.errors.full_messages_for(:attachment))
     end
   end
 
diff --git a/app/models/document.rb b/app/models/document.rb
index 108f29fad..e8524bc72 100644
--- a/app/models/document.rb
+++ b/app/models/document.rb
@@ -80,24 +80,24 @@ class Document < ActiveRecord::Base
     def validate_attachment_size
       if documentable_class.present? &&
          attachment_file_size > documentable_class.max_file_size
-        errors[:attachment] = I18n.t("documents.errors.messages.in_between",
+        errors.add(:attachment, I18n.t("documents.errors.messages.in_between",
                                       min: "0 Bytes",
-                                      max: "#{max_file_size(documentable_class)} MB")
+                                      max: "#{max_file_size(documentable_class)} MB"))
       end
     end
 
     def validate_attachment_content_type
       if documentable_class &&
          !accepted_content_types(documentable_class).include?(attachment_content_type)
-        errors[:attachment] = I18n.t("documents.errors.messages.wrong_content_type",
-                                      content_type: attachment_content_type,
-                                      accepted_content_types: documentable_humanized_accepted_content_types(documentable_class))
+        errors.add(:attachment, I18n.t("documents.errors.messages.wrong_content_type",
+                                   content_type: attachment_content_type,
+                                   accepted_content_types: documentable_humanized_accepted_content_types(documentable_class)))
       end
     end
 
     def attachment_presence
       if attachment.blank? && cached_attachment.blank?
-        errors[:attachment] = I18n.t("errors.messages.blank")
+        errors.add(:attachment, I18n.t("errors.messages.blank"))
       end
     end
 
diff --git a/app/models/image.rb b/app/models/image.rb
index 8f62f94d8..a782d1916 100644
--- a/app/models/image.rb
+++ b/app/models/image.rb
@@ -79,23 +79,23 @@ class Image < ActiveRecord::Base
     def validate_attachment_size
       if imageable_class &&
          attachment_file_size > 1.megabytes
-        errors[:attachment] = I18n.t("images.errors.messages.in_between",
-                                      min: "0 Bytes",
-                                      max: "#{imageable_max_file_size} MB")
+        errors.add(:attachment, I18n.t("images.errors.messages.in_between",
+                                     min: "0 Bytes",
+                                     max: "#{imageable_max_file_size} MB"))
       end
     end
 
     def validate_attachment_content_type
       if imageable_class && !attachment_of_valid_content_type?
-        errors[:attachment] = I18n.t("images.errors.messages.wrong_content_type",
-                                      content_type: attachment_content_type,
-                                      accepted_content_types: imageable_humanized_accepted_content_types)
+        errors.add(:attachment, I18n.t("images.errors.messages.wrong_content_type",
+                                     content_type: attachment_content_type,
+                                     accepted_content_types: imageable_humanized_accepted_content_types))
       end
     end
 
     def attachment_presence
       if attachment.blank? && cached_attachment.blank?
-        errors[:attachment] = I18n.t("errors.messages.blank")
+        errors.add(:attachment, I18n.t("errors.messages.blank"))
       end
     end