diff --git a/rc_shared.sh b/rc_shared.sh
index f044be7..b07862d 100644
--- a/rc_shared.sh
+++ b/rc_shared.sh
@@ -808,7 +808,7 @@ function pv-test {
 
 	read -p "Test presets? (y/N) " test_vpresets
 	if [[ "$test_vpresets" == "y"* ]]; then
-		vpresets="$vpresets slo fst med"
+		vpresets="$vpresets slw med fst"
 	fi
 	echo " presets: '$vpresets'"
 
@@ -897,15 +897,17 @@ function pv-test {
 								if [[ "$vpreset" != "skip" ]]; then
 									if [[ "$vcodec" == "libsvtav1" ]]; then
 										case $vpreset in
-											slo) preset="0" ;;
+											slw) preset="0" ;;
 											med) preset="6" ;;
 											fst) preset="13" ;;
+											*) echo "ERROR: Unhandled vpreset '${vpreset}', exiting." && return 1
 										esac
 									else
 										case $vpreset in
-											slo) preset="veryslow" ;;
+											slw) preset="veryslow" ;;
 											med) preset="medium" ;;
 											fst) preset="ultrafast" ;;
+											*) echo "ERROR: Unhandled vpreset '${vpreset}', exiting" && return 1
 										esac
 									fi
 									if [[ -n "$preset" ]]; then