diff --git a/interface/src/scripting/WindowScriptingInterface.cpp b/interface/src/scripting/WindowScriptingInterface.cpp
index 7cfbfb174e..fbeddf41e0 100644
--- a/interface/src/scripting/WindowScriptingInterface.cpp
+++ b/interface/src/scripting/WindowScriptingInterface.cpp
@@ -253,6 +253,16 @@ int WindowScriptingInterface::createMessageBox(QString title, QString text, int
 void WindowScriptingInterface::updateMessageBox(int id, QString title, QString text, int buttons, int defaultButton) {
     auto messageBox = _messageBoxes.value(id);
     if (messageBox) {
+        if (QThread::currentThread() != thread()) {
+            QMetaObject::invokeMethod(this, "updateMessageBox",
+                Q_ARG(int, id),
+                Q_ARG(QString, title),
+                Q_ARG(QString, text),
+                Q_ARG(int, buttons),
+                Q_ARG(int, defaultButton));
+            return;
+        }
+
         messageBox->setProperty("title", title);
         messageBox->setProperty("text", text);
         messageBox->setProperty("buttons", buttons);
@@ -263,6 +273,12 @@ void WindowScriptingInterface::updateMessageBox(int id, QString title, QString t
 void WindowScriptingInterface::closeMessageBox(int id) {
     auto messageBox = _messageBoxes.value(id);
     if (messageBox) {
+        if (QThread::currentThread() != thread()) {
+            QMetaObject::invokeMethod(this, "closeMessageBox",
+                Q_ARG(int, id));
+            return;
+        }
+
         disconnect(messageBox);
         messageBox->setVisible(false);
         messageBox->deleteLater();
diff --git a/scripts/system/html/js/marketplacesInject.js b/scripts/system/html/js/marketplacesInject.js
index d5f0f4cb06..10970a7749 100644
--- a/scripts/system/html/js/marketplacesInject.js
+++ b/scripts/system/html/js/marketplacesInject.js
@@ -24,7 +24,7 @@
 
     var canWriteAssets = false;
     var xmlHttpRequest = null;
-    var isDownloading = false;  // Explicitly track download request status.
+    var isPreparing = false;  // Explicitly track download request status.
 
     function injectCommonCode(isDirectoryPage) {
 
@@ -139,7 +139,7 @@
             function startAutoDownload() {
 
                 // One file request at a time.
-                if (isDownloading) {
+                if (isPreparing) {
                     console.log("WARNIKNG: Clara.io FBX: Prepare only one download at a time");
                     return;
                 }
@@ -178,7 +178,7 @@
                     var message = this.responseText.slice(responseTextIndex);
                     var statusMessage = "";
 
-                    if (isDownloading) {  // Ignore messages in flight after finished/cancelled.
+                    if (isPreparing) {  // Ignore messages in flight after finished/cancelled.
                         var lines = message.split(/[\n\r]+/);
 
                         for (var i = 0, length = lines.length; i < length; i++) {
@@ -222,33 +222,30 @@
                 xmlHttpRequest.onload = function () {
                     var statusMessage = "";
 
-                    if (!isDownloading) {
+                    if (!isPreparing) {
                         return;
                     }
 
+                    isPreparing = false;
+
                     var HTTP_OK = 200;
                     if (this.status !== HTTP_OK) {
                         statusMessage = "Zip file request terminated with " + this.status + " " + this.statusText;
                         console.log("ERROR: Clara.io FBX: " + statusMessage);
                         EventBridge.emitWebEvent(CLARA_IO_STATUS + " " + statusMessage);
-                        return;
-                    }
-
-                    if (zipFileURL.slice(-4) !== ".zip") {
+                    } else if (zipFileURL.slice(-4) !== ".zip") {
                         statusMessage = "Error creating zip file for download.";
                         console.log("ERROR: Clara.io FBX: " + statusMessage + ": " + zipFileURL);
                         EventBridge.emitWebEvent(CLARA_IO_STATUS + " " + statusMessage);
-                        return;
+                    } else {
+                        EventBridge.emitWebEvent(CLARA_IO_DOWNLOAD + " " + zipFileURL);
+                        console.log("Clara.io FBX: File download initiated for " + zipFileURL);
                     }
 
-                    EventBridge.emitWebEvent(CLARA_IO_DOWNLOAD + " " + zipFileURL);
-                    console.log("Clara.io FBX: File download initiated for " + zipFileURL);
-
                     xmlHttpRequest = null;
-                    isDownloading = false;
                 }
 
-                isDownloading = true;
+                isPreparing = true;
 
                 console.log("Clara.io FBX: Request zip file for " + uuid);
                 EventBridge.emitWebEvent(CLARA_IO_STATUS + " Initiating download");
@@ -301,7 +298,7 @@
     }
 
     function cancelClaraDownload() {
-        isDownloading = false;
+        isPreparing = false;
 
         if (xmlHttpRequest) {
             xmlHttpRequest.abort();