diff --git a/PhysicsTools/PatAlgos/plugins/LowPtGSFToPackedCandidateLinker.cc b/PhysicsTools/PatAlgos/plugins/LowPtGSFToPackedCandidateLinker.cc
index a82b2fd3ac561..bb913d8b50eb5 100644
--- a/PhysicsTools/PatAlgos/plugins/LowPtGSFToPackedCandidateLinker.cc
+++ b/PhysicsTools/PatAlgos/plugins/LowPtGSFToPackedCandidateLinker.cc
@@ -89,8 +89,8 @@ void LowPtGSFToPackedCandidateLinker::produce(edm::StreamID, edm::Event& iEvent,
   //store auxiliary mappings for association
   std::vector<int> gsf2pack(ngsf, -1);
   std::vector<int> gsf2lost(ngsf, -1);
-  PackedCandidatePtrCollection ele2packedptr(nele, PackedCandidatePtr(packed, -1));
-  PackedCandidatePtrCollection ele2lostptr(nele, PackedCandidatePtr(lost_tracks, -1));
+  PackedCandidatePtrCollection ele2packedptr(nele, PackedCandidatePtr());
+  PackedCandidatePtrCollection ele2lostptr(nele, PackedCandidatePtr());
 
   //electrons will never store their track (they store the Gsf track)
   //map PackedPF <--> Track
diff --git a/RecoVertex/PrimaryVertexProducer/src/DAClusterizerInZ_vect.cc b/RecoVertex/PrimaryVertexProducer/src/DAClusterizerInZ_vect.cc
index 00e86781117eb..72470403eee5e 100644
--- a/RecoVertex/PrimaryVertexProducer/src/DAClusterizerInZ_vect.cc
+++ b/RecoVertex/PrimaryVertexProducer/src/DAClusterizerInZ_vect.cc
@@ -1276,6 +1276,9 @@ vector<vector<reco::TransientTrack>> DAClusterizerInZ_vect::clusterize(
     const vector<reco::TransientTrack>& tracks) const {
   vector<vector<reco::TransientTrack>> clusters;
 
+  if (tracks.empty())
+    return clusters;
+
   vector<TransientVertex> pv;
   if (runInBlocks_ and (block_size_ < tracks.size()))  //doesn't bother if low number of tracks
     pv = vertices_in_blocks(tracks);