diff --git a/src/sunstone/sunstone-server.rb b/src/sunstone/sunstone-server.rb
index 6e12fff0c4..a2cf57a5d3 100755
--- a/src/sunstone/sunstone-server.rb
+++ b/src/sunstone/sunstone-server.rb
@@ -423,10 +423,15 @@ post '/upload'do
         tmpfile.flush
     else
         logger.error { "Unexpected rackinput class #{rackinput.class}" }
-        return [500, ""]
+        [500, ""]
     end
 
-    @SunstoneServer.upload(params[:img], tmpfile.path)
+    if tmpfile.size == 0
+        [500, OpenNebula::Error.new("There was a problem uploading the file, " \
+                "please check the permissions on the file").to_json]
+    else
+        @SunstoneServer.upload(params[:img], tmpfile.path)
+    end
 end
 
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