diff --git a/ci/build/npm-postinstall.sh b/ci/build/npm-postinstall.sh
index 3c2bcb2dbff0..29e46b388220 100755
--- a/ci/build/npm-postinstall.sh
+++ b/ci/build/npm-postinstall.sh
@@ -67,7 +67,7 @@ main() {
 
   if [ "$major_node_version" -ne "${FORCE_NODE_VERSION:-24}" ]; then
     echo "ERROR: code-server currently requires node v24."
-    if [ -n "$FORCE_NODE_VERSION" ]; then
+    if [ -n "${FORCE_NODE_VERSION:-}" ]; then
       echo "However, you have overrided the version check to use v$FORCE_NODE_VERSION."
     fi
     echo "We have detected that you are on node v$major_node_version"