diff --git a/wGRR b/wGRR
index 0b57da680dcd8007a111ae91e033538eb559a016..4767a926013ac190f75861217d474be8fa11d52d 100755
--- a/wGRR
+++ b/wGRR
@@ -169,6 +169,9 @@ fi
 printf "%-10s  --  %s\n" "[INFO]" "wGRR version ${VERSION}" | tee -a ${OUT}.wgrr.log
 
 if [[ $BATCHFLAG == 0 ]] ; then
+	if [[ $FAST == 1 ]] ; then
+		printf "%-10s  --  %s\n" "[WARNING]" "The fast flag (-f) is useless when not using sbatch"  | tee -a ${OUT}.wgrr.log
+	fi
 	if [[ $THREADS -gt $(nproc) ]] ; then
 		printf "%-10s  --  %s\n" "[ERROR]" "You required $THREADS threads but your machine has $(nproc) cores."  | tee -a ${OUT}.wgrr.log
 		exit 1