diff --git a/src/Root/SkinDetectorWriter.cpp b/src/Root/SkinDetectorWriter.cpp
index 726b762..0d92e3e 100644
--- a/src/Root/SkinDetectorWriter.cpp
+++ b/src/Root/SkinDetectorWriter.cpp
@@ -5,13 +5,16 @@
 SkinDetectorWriter::SkinDetectorWriter(string filename) :
     t_file(nullptr),
     t_tree(nullptr),
-    t_buffer(nullptr)
+    t_buffer(nullptr),
+    i_status(0)
 {
     t_file = new TFile(filename.c_str(), "RECREATE");
     t_tree = new TTree("muCastorMC", "muCastorMC");
     t_buffer = new TClonesArray("muCastorSkinHit");
 
     t_tree->Branch("CastorSkinHits", "TClonesArray", t_buffer, 32000, 99);
+
+    if (t_file->IsZombie()) i_status = 1;
 }
 
 SkinDetectorWriter::~SkinDetectorWriter()
@@ -30,14 +33,15 @@ void SkinDetectorWriter::add(int detID, float p_x, float p_y, float p_z,
     new_hit->SetPos (TVector3(p_x, p_y, p_z));
     new_hit->SetMom (TVector3(m_x, m_y, m_z));
 }
+
 void SkinDetectorWriter::write()
 {
-    t_tree->Fill();
+    if (t_tree->Fill() < 0) i_status = 2;
     t_buffer->Delete();   // or t_buffer->Clear() ??
 }
 
 void SkinDetectorWriter::close()
 {
-    t_tree->Write();
+    if (t_tree->Write() == 0) i_status = 3;
     t_file->Close();
 }
\ No newline at end of file
diff --git a/src/Root/SkinDetectorWriter.h b/src/Root/SkinDetectorWriter.h
index 8025c63..714c7da 100644
--- a/src/Root/SkinDetectorWriter.h
+++ b/src/Root/SkinDetectorWriter.h
@@ -16,6 +16,7 @@ public:
     virtual ~SkinDetectorWriter();
 
     void add(int detID, float p_x, float p_y, float p_z, float m_x, float m_y, float m_z);
+    int status() { return i_status; }
     void write();
     void close();
 
@@ -23,6 +24,7 @@ private:
     TFile* t_file;
     TTree* t_tree;
     TClonesArray* t_buffer;
+    int i_status;
 };