diff --git a/interface/resources/qml/AssetServer.qml b/interface/resources/qml/AssetServer.qml
index afb4b50773..a178374fed 100644
--- a/interface/resources/qml/AssetServer.qml
+++ b/interface/resources/qml/AssetServer.qml
@@ -72,12 +72,16 @@ Window {
 
     }
     function doRenameFile(oldPath, newPath) {
-        console.log("Renaming " + oldPath + " to " + newPath);
-
         if (newPath[0] != "/") {
             newPath = "/" + newPath;
         }
 
+        if (Assets.isKnownFolder(newPath)) {
+            box = errorMessageBox("Cannot overwrite existing directory.");
+            box.selected.connect(reload);
+        }
+
+        console.log("Renaming " + oldPath + " to " + newPath);
         Assets.renameMapping(oldPath, newPath, function(err) {
             if (err) {
                 console.log("Error renaming: ", oldPath, "=>", newPath, " - error ", err);
@@ -110,9 +114,8 @@ Window {
         });
     }
 
-    function canAddToWorld() {
+    function canAddToWorld(path) {
         var supportedExtensions = [/\.fbx\b/i, /\.obj\b/i];
-        var path = assetProxyModel.data(treeView.currentIndex, 0x100);
 
         return supportedExtensions.reduce(function(total, current) {
             return total | new RegExp(current).test(path);
@@ -133,7 +136,7 @@ Window {
 
     function addToWorld() {
         var url = assetProxyModel.data(treeView.currentIndex, 0x103);
-        if (!url) {
+        if (!url || !canAddToWorld(url)) {
             return;
         }
         var addPosition = Vec3.sum(MyAvatar.position, Vec3.multiply(2, Quat.getFront(MyAvatar.orientation)));
@@ -284,7 +287,7 @@ Window {
                     height: 26
                     width: 120
 
-                    enabled: canAddToWorld()
+                    enabled: canAddToWorld(assetProxyModel.data(treeView.currentIndex, 0x100))
 
                     onClicked: root.addToWorld()
                 }
@@ -404,6 +407,9 @@ Window {
                 anchors.rightMargin: uploadButton.width + hifi.dimensions.contentSpacing.x
 
                 text: "Add to world on upload"
+
+                opacity: canAddToWorld(fileUrlTextField.text) ? 1 : 0
+
                 checked: false
             }
 
diff --git a/interface/src/scripting/AssetMappingsScriptingInterface.cpp b/interface/src/scripting/AssetMappingsScriptingInterface.cpp
index 6ac60ccbdf..ae2ef3183a 100644
--- a/interface/src/scripting/AssetMappingsScriptingInterface.cpp
+++ b/interface/src/scripting/AssetMappingsScriptingInterface.cpp
@@ -174,6 +174,19 @@ void AssetMappingsScriptingInterface::renameMapping(QString oldPath, QString new
     request->start();
 }
 
+bool AssetMappingModel::isKnownFolder(QString path) const {
+    if (!path.endsWith("/")) {
+        return false;
+    }
+
+    auto existingPaths = _pathToItemMap.keys();
+    for (auto& entry : existingPaths) {
+        if (entry.startsWith(path)) {
+            return true;
+        }
+    }
+    return false;
+}
 
 AssetMappingItem::AssetMappingItem(const QString& name, const QString& fullPath, bool isFolder) :
     name(name),
diff --git a/interface/src/scripting/AssetMappingsScriptingInterface.h b/interface/src/scripting/AssetMappingsScriptingInterface.h
index 3a7711b340..99ced25d29 100644
--- a/interface/src/scripting/AssetMappingsScriptingInterface.h
+++ b/interface/src/scripting/AssetMappingsScriptingInterface.h
@@ -35,7 +35,8 @@
  public:
      Q_INVOKABLE void refresh();
 
-     bool isKnownMapping(QString path) const { return _pathToItemMap.contains(path); };
+     bool isKnownMapping(QString path) const { return _pathToItemMap.contains(path); }
+     bool isKnownFolder(QString path) const;
 
  signals:
      void errorGettingMappings(int error);
@@ -55,7 +56,8 @@ public:
     Q_INVOKABLE AssetMappingModel* getAssetMappingModel() { return &_assetMappingModel; }
     Q_INVOKABLE QAbstractProxyModel* getProxyModel() { return &_proxyModel; }
 
-    Q_INVOKABLE bool isKnownMapping(QString path) const { return _assetMappingModel.isKnownMapping(path); };
+    Q_INVOKABLE bool isKnownMapping(QString path) const { return _assetMappingModel.isKnownMapping(path); }
+    Q_INVOKABLE bool isKnownFolder(QString path) const { return _assetMappingModel.isKnownFolder(path); }
 
     Q_INVOKABLE QString getErrorString(int errorCode) const;