diff --git a/trick_source/data_products/Log/MatLab4.cpp b/trick_source/data_products/Log/MatLab4.cpp
index 3f6186f6..a33bf191 100644
--- a/trick_source/data_products/Log/MatLab4.cpp
+++ b/trick_source/data_products/Log/MatLab4.cpp
@@ -364,6 +364,9 @@ int MatLab4LocateParam( char *file_name , char *param_name , char *time_name ) {
                         case 5:
                                 size = 1 ;
                                 break ;
+                        default :
+                                std::cerr << "Matlab4 "__FUNCTION__ << "ERROR: invalid matrix size" << std::endl;
+                                size = -1; 
                 }
 
                 fread( &row , 4 , 1 , fp ) ;