diff --git a/interface/resources/images/Default-Sky-9-ambient.jpg b/interface/resources/images/Default-Sky-9-ambient.jpg
deleted file mode 100644
index 8fb383c5e8..0000000000
Binary files a/interface/resources/images/Default-Sky-9-ambient.jpg and /dev/null differ
diff --git a/interface/resources/images/Default-Sky-9-cubemap.jpg b/interface/resources/images/Default-Sky-9-cubemap.jpg
deleted file mode 100644
index 697fd9aeea..0000000000
Binary files a/interface/resources/images/Default-Sky-9-cubemap.jpg and /dev/null differ
diff --git a/interface/resources/images/Default-Sky-9-cubemap.ktx b/interface/resources/images/Default-Sky-9-cubemap.ktx
new file mode 100644
index 0000000000..95710d2c08
Binary files /dev/null and b/interface/resources/images/Default-Sky-9-cubemap.ktx differ
diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index 32f6d9554e..f4699009ac 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -1438,15 +1438,17 @@ Application::Application(int& argc, char** argv, QElapsedTimer& startupTimer, bo
     connect(_window, SIGNAL(windowMinimizedChanged(bool)), this, SLOT(windowMinimizedChanged(bool)));
     qCDebug(interfaceapp, "Startup time: %4.2f seconds.", (double)startupTimer.elapsed() / 1000.0);
 
-    auto textureCache = DependencyManager::get<TextureCache>();
+    {
+        PROFILE_RANGE(render, "Process Default Skybox");
+        auto textureCache = DependencyManager::get<TextureCache>();
 
-    QString skyboxUrl { PathUtils::resourcesPath() + "images/Default-Sky-9-cubemap.jpg" };
-    QString skyboxAmbientUrl { PathUtils::resourcesPath() + "images/Default-Sky-9-ambient.jpg" };
+        auto skyboxUrl = PathUtils::resourcesPath().toStdString() + "images/Default-Sky-9-cubemap.ktx";
 
-    _defaultSkyboxTexture = textureCache->getImageTexture(skyboxUrl, image::TextureUsage::CUBE_TEXTURE, { { "generateIrradiance", false } });
-    _defaultSkyboxAmbientTexture = textureCache->getImageTexture(skyboxAmbientUrl, image::TextureUsage::CUBE_TEXTURE, { { "generateIrradiance", true } });
+        _defaultSkyboxTexture = gpu::Texture::unserialize(skyboxUrl);
+        _defaultSkyboxAmbientTexture = _defaultSkyboxTexture;
 
-    _defaultSkybox->setCubemap(_defaultSkyboxTexture);
+        _defaultSkybox->setCubemap(_defaultSkyboxTexture);
+    }
 
     EntityItem::setEntitiesShouldFadeFunction([this]() {
         SharedNodePointer entityServerNode = DependencyManager::get<NodeList>()->soloNodeOfType(NodeType::EntityServer);
diff --git a/libraries/shared/src/shared/Storage.cpp b/libraries/shared/src/shared/Storage.cpp
index aae1f8455f..f6585e6ecb 100644
--- a/libraries/shared/src/shared/Storage.cpp
+++ b/libraries/shared/src/shared/Storage.cpp
@@ -68,7 +68,7 @@ StoragePointer FileStorage::create(const QString& filename, size_t size, const u
 }
 
 FileStorage::FileStorage(const QString& filename) : _file(filename) {
-    if (_file.open(QFile::ReadWrite)) {
+    if (_file.open(QFile::ReadOnly)) {
         _mapped = _file.map(0, _file.size());
         if (_mapped) {
             _valid = true;
@@ -90,3 +90,34 @@ FileStorage::~FileStorage() {
         _file.close();
     }
 }
+
+void FileStorage::ensureWriteAccess() {
+    if (_hasWriteAccess) {
+        return;
+    }
+
+    if (_mapped) {
+        if (!_file.unmap(_mapped)) {
+            throw std::runtime_error("Unable to unmap file");
+        }
+    }
+    if (_file.isOpen()) {
+        _file.close();
+    }
+    _valid = false;
+    _mapped = nullptr;
+
+    if (_file.open(QFile::ReadWrite)) {
+        _mapped = _file.map(0, _file.size());
+        if (_mapped) {
+            _valid = true;
+            _hasWriteAccess = true;
+        } else {
+            qCWarning(storagelogging) << "Failed to map file " << _file.fileName();
+            throw std::runtime_error("Failed to map file");
+        }
+    } else {
+        qCWarning(storagelogging) << "Failed to open file " << _file.fileName();
+        throw std::runtime_error("Failed to open file");
+    }
+}
\ No newline at end of file
diff --git a/libraries/shared/src/shared/Storage.h b/libraries/shared/src/shared/Storage.h
index da5b773d52..4cad9fa083 100644
--- a/libraries/shared/src/shared/Storage.h
+++ b/libraries/shared/src/shared/Storage.h
@@ -60,11 +60,14 @@ namespace storage {
         FileStorage& operator=(const FileStorage& other) = delete;
 
         const uint8_t* data() const override { return _mapped; }
-        uint8_t* mutableData() override { return _mapped; }
+        uint8_t* mutableData() override { ensureWriteAccess(); return _mapped; }
         size_t size() const override { return _file.size(); }
         operator bool() const override { return _valid; }
     private:
+        void ensureWriteAccess();
+
         bool _valid { false };
+        bool _hasWriteAccess { false };
         QFile _file;
         uint8_t* _mapped { nullptr };
     };