diff --git a/src/obi_clean.c b/src/obi_clean.c
index efc044f..0c367a3 100755
--- a/src/obi_clean.c
+++ b/src/obi_clean.c
@@ -18,6 +18,7 @@
 #include <stdbool.h>
 #include <search.h>
 #include <sys/time.h>
+#include <math.h>
 
 #include "obi_clean.h"
 #include "obidms.h"
@@ -426,7 +427,7 @@ int obi_clean(const char* dms_name,
 			byte_t 	   ali_result;
 
 			// Parallelize the loop on samples to avoid interdependency issues inside one sample
-			#pragma omp for schedule(dynamic, (sample_count/thread_count))
+			#pragma omp for schedule(dynamic, sample_count/thread_count + (sample_count % thread_count != 0))  // Avoid 0 which blocks the program
 			for (sample=0; sample < sample_count; sample++)
 			{
 				sample_count_array = complete_sample_count_array+(sample*seq_count);