diff --git a/lib/clean/system.sh b/lib/clean/system.sh
index 5cc5e93..982ac32 100644
--- a/lib/clean/system.sh
+++ b/lib/clean/system.sh
@@ -186,7 +186,7 @@ clean_deep_system() {
         done < <(sudo find "$mem_reports_dir" -type f -mtime +30 -print0 2> /dev/null || true)
 
         if [[ "$file_count" -gt 0 ]]; then
-            if [[ "$DRY_RUN" != "true" ]]; then
+            if [[ "${DRY_RUN:-}" != "true" ]]; then
                 if safe_sudo_find_delete "$mem_reports_dir" "*" "30" "f"; then
                     mem_cleaned=1
                 fi