diff --git a/plugins/clock_tree_extractor/CMakeLists.txt b/plugins/clock_tree_extractor/CMakeLists.txt
index 79624f6aafc..180367f058b 100644
--- a/plugins/clock_tree_extractor/CMakeLists.txt
+++ b/plugins/clock_tree_extractor/CMakeLists.txt
@@ -1,4 +1,4 @@
-option(PL_CLOCK_TREE_EXTRACTOR "PL_CLOCK_TREE_EXTRACTOR" ON)
+option(PL_CLOCK_TREE_EXTRACTOR "PL_CLOCK_TREE_EXTRACTOR" OFF)
 
 if(PL_CLOCK_TREE_EXTRACTOR OR BUILD_ALL_PLUGINS)
 
diff --git a/plugins/clock_tree_extractor/src/clock_tree.cpp b/plugins/clock_tree_extractor/src/clock_tree.cpp
index 227779bd4c6..2f38f687b16 100644
--- a/plugins/clock_tree_extractor/src/clock_tree.cpp
+++ b/plugins/clock_tree_extractor/src/clock_tree.cpp
@@ -652,14 +652,14 @@ namespace hal
             for( igraph_integer_t idx = 0; idx < igraph_vector_int_size( &map ); idx++ )
             {
                 const igraph_integer_t vertex = VECTOR( map )[idx];
-                if( vertex == 0 )
+                if( vertex == -1 )
                 {
                     continue;
                 }
 
                 const void *ptr = m_vertices_to_ptrs.at( idx );
 
-                vertices_to_ptrs[vertex - 1] = ptr;
+                vertices_to_ptrs[vertex] = ptr;
                 ptrs_to_types[ptr] = m_ptrs_to_types.at( ptr );
             }