diff --git a/poky/scripts/lib/buildstats.py b/poky/scripts/lib/buildstats.py
index d9aadf3..f7db3ea 100644
--- a/poky/scripts/lib/buildstats.py
+++ b/poky/scripts/lib/buildstats.py
@@ -263,7 +263,7 @@
         """Aggregate other buildstats into this"""
         if set(self.keys()) != set(buildstats.keys()):
             raise ValueError("Refusing to aggregate buildstats, set of "
-                             "recipes is different")
+                             "recipes is different: %s" % (set(self.keys()) ^ set(buildstats.keys())))
         for pkg, data in buildstats.items():
             self[pkg].aggregate(data)