diff --git a/src/logger.c b/src/logger.c
index 2c07d4ac575ebceffebeafe01e97ec2cc96acd9c..4c3dd6190bbb65df12e2cce9b62da1bfdb578926 100644
--- a/src/logger.c
+++ b/src/logger.c
@@ -304,9 +304,7 @@ void logger_write_file_header(struct dump *dump) {
   memcpy(buff, LOGGER_VERSION, LOGGER_VERSION_SIZE);
  
   /* write number of bytes used for the offsets */
-  message("Start %lu", *file_offset);
   buff = dump_get(dump, LOGGER_OFFSET_SIZE, file_offset);
-  message("End %lu", *file_offset);
   memcpy(buff, &log_const.offset, LOGGER_OFFSET_SIZE);
 
   /* will write the offset of the first particle here */
@@ -320,6 +318,7 @@ void logger_write_file_header(struct dump *dump) {
   buff = dump_get(dump, LOGGER_NBER_SIZE, file_offset);
   memcpy(buff, &log_const.number, LOGGER_NBER_SIZE);
 
+  /* write masks */
   mask_size = log_const.nber_mask * (log_const.name + log_const.mask);
   name_buff = dump_get(dump, mask_size, file_offset);
   for(i=0; i<log_const.nber_mask; i++) {
@@ -337,6 +336,7 @@ void logger_write_file_header(struct dump *dump) {
 
   /* last step */
   memcpy(skip_header, file_offset, log_const.offset);
+  message("First offset %lu", *file_offset);
   logger_const_free(&log_const);
 }
 
@@ -346,7 +346,7 @@ void logger_const_init(struct logger_const* log_const) {
   log_const->mask = 1;
   log_const->number = 1;
 
-  log_const->nber_mask = 8;
+  log_const->nber_mask = 1;
 
   char *cur_name;
   char tmp[log_const->name];
diff --git a/src/logger.h b/src/logger.h
index 3585131ccc6f8be1a26e57f8717e7536191baebd..68562141a40cf9cba8462e5931884c6eeffd7226 100644
--- a/src/logger.h
+++ b/src/logger.h
@@ -84,7 +84,7 @@ struct dump;
  * Size in bytes
  */
 #define LOGGER_VERSION_SIZE 20 // size of the version message
-#define LOGGER_NAME_SIZE 1 // size of the labels
+#define LOGGER_NAME_SIZE 2 // size of the labels
 #define LOGGER_MASK_SIZE 1 // size of the masks
 #define LOGGER_NBER_SIZE 1 // size of the number of elements
 #define LOGGER_OFFSET_SIZE 1// size of the offset size information