diff --git a/src/openrct2-ui/windows/ProgressWindow.cpp b/src/openrct2-ui/windows/ProgressWindow.cpp
index 9f88d70d09..22d9e1b3b3 100644
--- a/src/openrct2-ui/windows/ProgressWindow.cpp
+++ b/src/openrct2-ui/windows/ProgressWindow.cpp
@@ -71,12 +71,12 @@ namespace OpenRCT2::Ui::Windows
     private:
         CloseCallback _onClose = nullptr;
 
-        StringId _progressFormat;
+        StringId _progressFormat{ kStringIdEmpty };
         std::string _progressTitle;
         std::string _currentCaption;
 
-        uint32_t _currentProgress;
-        uint32_t _totalCount;
+        uint32_t _currentProgress{};
+        uint32_t _totalCount{};
         int8_t style = -1;
 
     public: