--- a/docs/data_processing/pre_exit_codes.rst	Sun Sep 28 21:19:05 2014 +0200
+++ b/docs/data_processing/pre_exit_codes.rst	Wed Oct 01 18:49:04 2014 +0200
@@ -41,7 +41,9 @@
    Found wrong value(s) for variable 'Dead_Time_Corr_Type' in NetCDF file or in SCC_DB
 
 23
-   Found negative number of counts in lidar data!
+   Found negative number of counts in lidar data! Note: This error could also 
+   result when photocounting values are not compatible with the used dead time 
+   correction value. 
 
 24
    Found wrong value(s) in variable 'Raw_Bck_Start_Time' end/or 'Raw_Bck_Stop_Time' and/or in laser repetition rate value