diff --git a/src/dtmc/atomic_proposition.h b/src/dtmc/atomic_proposition.h
index 19acc9e16..3af284cc9 100644
--- a/src/dtmc/atomic_proposition.h
+++ b/src/dtmc/atomic_proposition.h
@@ -51,9 +51,11 @@ class AtomicProposition {
 	void initialize(uint_fast32_t nodeCount) {
 	   if (node_array == NULL) {
 	      node_count = nodeCount;
-	      node_array = new uint_fast64_t[(int) std::ceil(nodeCount / 64)]();
-	      if (node_array == NULL) {
-	         throw std::bad_alloc();
+	      int n = (int) std::ceil(nodeCount / 64.0);
+	      node_array = new uint_fast64_t[n];
+	      //Initialization with 0 is crucial!
+	      for (int i = 0; i < n; i++) {
+	         node_array[i] = 0L;
 	      }
 	   }
 
diff --git a/test/parser/read_lab_file_test.cpp b/test/parser/read_lab_file_test.cpp
index e7fa6bcb9..2702ddf3f 100644
--- a/test/parser/read_lab_file_test.cpp
+++ b/test/parser/read_lab_file_test.cpp
@@ -75,3 +75,15 @@ TEST(ReadLabFileTest, ParseTest) {
    //Deleting the labelling
    delete labelling;
 }
+
+TEST(ReadLabFileTest, WrongHeaderTest1) {
+   ASSERT_THROW(mrmc::parser::read_lab_file(3,"test/parser/lab_files/wrong_format_header1.lab"), mrmc::exceptions::wrong_file_format);
+}
+
+TEST(ReadLabFileTest, WrongHeaderTest2) {
+   ASSERT_THROW(mrmc::parser::read_lab_file(3,"test/parser/lab_files/wrong_format_header2.lab"), mrmc::exceptions::wrong_file_format);
+}
+
+TEST(ReadLabFileTest, WrongPropositionTest) {
+   ASSERT_THROW(mrmc::parser::read_lab_file(3,"test/parser/lab_files/wrong_format_proposition.lab"), mrmc::exceptions::wrong_file_format);
+}