diff --git a/network-poc/static/index.html b/network-poc/static/index.html
index d242c40..71ca410 100644
--- a/network-poc/static/index.html
+++ b/network-poc/static/index.html
@@ -2271,6 +2271,10 @@ IMPORTANT: Include get_db() dependency for FastAPI` },
             const card = document.getElementById(cardId);
             if (!card) return;
             const files = projectFiles[cardId];
+            if (!files || Object.keys(files).length === 0) {
+                alert('Tiedostot eivät ole enää muistissa — aja pipeline uudelleen.');
+                return;
+            }
 
             // CRC-32 laskenta ZIP-tiedostoille
             function crc32(bytes) {
@@ -2291,7 +2295,7 @@ IMPORTANT: Include get_db() dependency for FastAPI` },
 
             for (const [name, content] of entries) {
                 const nameBytes = new TextEncoder().encode(name);
-                const contentBytes = new TextEncoder().encode(content);
+                const contentBytes = new TextEncoder().encode(content || '');
                 const crc = crc32(contentBytes);
 
                 // Local file header