diff --git a/workflow/main.nf b/workflow/main.nf
index a899d82ddbfd752cf2e7751b25c0326c421c6638..99f81a3ef93f63fee480ab52fa896cde1a5d5c20 100755
--- a/workflow/main.nf
+++ b/workflow/main.nf
@@ -18,7 +18,7 @@ if( params.refIndex ){
     .fromPath(params.refIndex)
     .ifEmpty { exit 1, "referene not found: ${params.refIndex}" }
 } else {
-  exit 1, "No reference genome specified."
+  exit 1, "No reference genome specified. ${params.genome}"
 }
 
 // Define List of Files