diff --git a/src/web/waiters/BackgroundWorkerWaiter.mjs b/src/web/waiters/BackgroundWorkerWaiter.mjs
index ed9f8c29..a7f9b83a 100644
--- a/src/web/waiters/BackgroundWorkerWaiter.mjs
+++ b/src/web/waiters/BackgroundWorkerWaiter.mjs
@@ -68,6 +68,7 @@ class BackgroundWorkerWaiter {
                 break;
             case "optionUpdate":
             case "statusMessage":
+            case "progressMessage":
                 // Ignore these messages
                 break;
             default:
diff --git a/src/web/waiters/OutputWaiter.mjs b/src/web/waiters/OutputWaiter.mjs
index 5e5ebeba..39b41cf1 100755
--- a/src/web/waiters/OutputWaiter.mjs
+++ b/src/web/waiters/OutputWaiter.mjs
@@ -975,7 +975,9 @@ class OutputWaiter {
         }
         tabStr = tabStr.slice(0, 200);
         this.manager.tabs.updateOutputTabHeader(inputNum, tabStr);
-        this.manager.tabs.updateOutputTabProgress(inputNum, this.outputs[inputNum].progress, this.manager.worker.recipeConfig.length);
+        if (this.manager.worker.recipeConfig !== undefined) {
+            this.manager.tabs.updateOutputTabProgress(inputNum, this.outputs[inputNum].progress, this.manager.worker.recipeConfig.length);
+        }
 
         const tabItem = this.manager.tabs.getOutputTabItem(inputNum);
         if (tabItem) {