Index: app/models/version.rb
===================================================================
--- app/models/version.rb	(revision 17852)
+++ app/models/version.rb	(working copy)
@@ -351,7 +351,7 @@
   end
 
   def deletable?
-    fixed_issues.empty? && !referenced_by_a_custom_field?
+    fixed_issues.empty? && !referenced_by_a_custom_field? && attachments.blank?
   end
 
   def default_project_version