diff --git a/scripts/install-multi-user.sh b/scripts/install-multi-user.sh
index 7c8e159b5..1431857d5 100644
--- a/scripts/install-multi-user.sh
+++ b/scripts/install-multi-user.sh
@@ -349,6 +349,11 @@ _sudo() {
 }
 
 
+# Ensure that $TMPDIR exists if defined.
+if [[ -v TMPDIR ]]; then
+    mkdir -m 0700 -p "$TMPDIR"
+fi
+
 readonly SCRATCH=$(mktemp -d)
 finish_cleanup() {
     rm -rf "$SCRATCH"