diff --git a/backend/src/db.js b/backend/src/db.js
index 04c7002..c68656c 100644
--- a/backend/src/db.js
+++ b/backend/src/db.js
@@ -165,7 +165,7 @@ if (!fileCols.includes('folder_id')) db.exec("ALTER TABLE files ADD COLUMN folde
 const fsTableExists = db.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name='folder_shares'").get();
 if (fsTableExists) {
   const fsCols = db.prepare("PRAGMA table_info(folder_shares)").all().map(r => r.name);
-  if (!fsCols.includes('created_at')) db.exec("ALTER TABLE folder_shares ADD COLUMN created_at DATETIME DEFAULT CURRENT_TIMESTAMP");
+  if (!fsCols.includes('created_at')) db.exec("ALTER TABLE folder_shares ADD COLUMN created_at DATETIME DEFAULT NULL");
 }
 
 const oiCols = db.prepare("PRAGMA table_info(order_items)").all().map(r => r.name);