diff --git a/arangod/Aql/Functions.cpp b/arangod/Aql/Functions.cpp
index 2607e3b3c6..6176c0094a 100644
--- a/arangod/Aql/Functions.cpp
+++ b/arangod/Aql/Functions.cpp
@@ -3186,8 +3186,10 @@ AqlValue Functions::Shift(arangodb::aql::Query* query,
 
     auto iterator = VPackArrayIterator(l);
     // This jumps over the first element
-    while (iterator.next()) {
+    iterator.next();
+    while (iterator.valid()) {
       builder->add(iterator.value());
+      iterator.next();
     }
   }
   builder->close();
diff --git a/arangod/Aql/Graphs.cpp b/arangod/Aql/Graphs.cpp
index 6881d353f5..d8cd364ba8 100644
--- a/arangod/Aql/Graphs.cpp
+++ b/arangod/Aql/Graphs.cpp
@@ -108,14 +108,26 @@ Graph::Graph(VPackSlice const& info) : _vertexColls(), _edgeColls() {
 
     for (auto const& def : VPackArrayIterator(edgeDefs)) {
       TRI_ASSERT(def.isObject());
-      std::string eCol = arangodb::basics::VelocyPackHelper::getStringValue(
+      try {
+        std::string eCol = arangodb::basics::VelocyPackHelper::getStringValue(
           def, "collection", "");
-      addEdgeCollection(eCol);
+        addEdgeCollection(eCol);
+      } catch (...) {
+        THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_GRAPH_INVALID_GRAPH, "didn't find 'collection' in the graph definition");
+      }
       // TODO what if graph is not in a valid format any more
-      VPackSlice tmp = def.get("from");
-      insertVertexCollections(tmp);
-      tmp = def.get("to");
-      insertVertexCollections(tmp);
+      try {
+        VPackSlice tmp = def.get("from");
+        insertVertexCollections(tmp);
+      } catch (...) {
+        THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_GRAPH_INVALID_GRAPH, "didn't find from-collection in the graph definition");
+      }
+      try {
+        VPackSlice tmp = def.get("to");
+        insertVertexCollections(tmp);
+      } catch (...) {
+        THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_GRAPH_INVALID_GRAPH, "didn't find to-collection in the graph definition");
+      }
     }
   }
   if (slice.hasKey(_attrOrphans)) {